## Summary
Assertions handler is too large and not working. This PR extracts the SDK v2 to v3 features into a separate package.
Reduces bundled size from `25.8mb` to `1.9mb` and restores the handlers functionality.

```bash
$ esbuild --bundle lib/assertions/providers/lambda-handler/index.ts --target=node14 --platform=node --outfile=lib/assertions/providers/lambda-handler.bundle/index.js

  lib/assertions/providers/lambda-handler.bundle/index.js  1.9mb ⚠️
```

## Why need this change?
After merged #26271, Assertions lambda function throw error at initialize phase and not working. This reason of problem is maybe to import `aws-cdk-lib/custom-resources` to use aws-sdk v2-v3 translate features. 
`aws-cdk-lib/custom-resources` exports the some constructs, so when import the package, then bundle size is too large and lambda function is not working.

```log
INIT_START Runtime Version: nodejs:18.v8	Runtime Version ARN: arn:aws:lambda:us-east-1::runtime:2755dc322c8dbb64760145d6403d14432af527bf4dd3cf03713aae10e0f8b552
--
2023-07-13T05:49:25.501Z	undefined	ERROR	Uncaught Exception     {
    "errorType": "TypeError",
    "errorMessage": "Class extends value undefined is not a constructor or null",
    "stack": [
        "TypeError: Class extends value undefined is not a constructor or null",
        "    at ../../aws-cdk-lib/core/lib/cfn-condition.ts (/var/task/index.js:796267:5)",
        "    at __init (/var/task/index.js:9:56)",
        "    at ../../aws-cdk-lib/core/lib/private/metadata-resource.ts (/var/task/index.js:807546:5)",
        "    at __init (/var/task/index.js:9:56)",
        "    at ../../aws-cdk-lib/core/lib/private/synthesis.ts (/var/task/index.js:814923:5)",
        "    at __init (/var/task/index.js:9:56)",
        "    at ../../aws-cdk-lib/core/lib/app.ts (/var/task/index.js:814951:5)",
        "    at __init (/var/task/index.js:9:56)",
        "    at ../../aws-cdk-lib/core/lib/stack.ts (/var/task/index.js:816555:5)",
        "    at __init (/var/task/index.js:9:56)"
    ]
}
START RequestId: b6da27f5-d7ff-4f76-807b-c7f5d1f02d1f Version: $LATEST
Unknown application error occurredRuntime.Unknown
END RequestId: b6da27f5-d7ff-4f76-807b-c7f5d1f02d1f
REPORT RequestId: b6da27f5-d7ff-4f76-807b-c7f5d1f02d1f	Duration: 13083.91 ms	Billed Duration: 13084 ms	Memory Size: 128 MB	Max Memory Used: 128 MB
```

## Solution

Extract the SDK v2 to v3 features into a new private package that can be bundled safely.
Also required changes to the `aws-custom-resource` v3 handler so it can used the shared code.
To make sure that the bundled files are free of start-up errors, I have added them into a post build script.

## Additional changes

**Update to Encode/Decode logic**
All parameters passed to a Custom Resource will be converted to string when passed to the Lambda Function handler. 
This is a feature/limitation by CloudFormation.
The previous implementation supported special handling for boolean values via a magic string.
However with the SDK v3 parameter types on API Calls are more strictly enforced, e.g. we can't pass a string anymore when a number is expected.
Therefore the encoding/decoding logic has been updated to indiscriminately encode _all_ parameters with `JSON.stringify()` and reverse the operation inside the assertions provider.

**Lambda Invoke Payload**
Withe the SDK v3, the type of the Payload returned from a Lambda Invoke operation is now a Buffer.
This makes sense from an SDK perspective since the returned payload might be a binary.
However assertions can only deal with JSON payloads, so we attempt to convert and parse the payload into a JSON object.
If that fails it stays unchanged.

## Acknowledgements 

Thanks @WinterYukky  for the initial investigation!

Closes #26359
Replaces #26360

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Fixes some issues with finding and calling v3 sdk clients.

Exports some utilities from `aws-cdk-lib.AwsCustomResource` for finding and calling `@aws-sdk/client-*` modules to avoid duplicating this logic.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

## Summary
Assertions handler is too large and not working. This PR extracts the SDK v2 to v3 features into a separate package.
Reduces bundled size from `25.8mb` to `1.9mb` and restores the handlers functionality.

```bash
$ esbuild --bundle lib/assertions/providers/lambda-handler/index.ts --target=node14 --platform=node --outfile=lib/assertions/providers/lambda-handler.bundle/index.js

  lib/assertions/providers/lambda-handler.bundle/index.js  1.9mb ⚠️
```

## Why need this change?
After merged aws#26271, Assertions lambda function throw error at initialize phase and not working. This reason of problem is maybe to import `aws-cdk-lib/custom-resources` to use aws-sdk v2-v3 translate features. 
`aws-cdk-lib/custom-resources` exports the some constructs, so when import the package, then bundle size is too large and lambda function is not working.

```log
INIT_START Runtime Version: nodejs:18.v8	Runtime Version ARN: arn:aws:lambda:us-east-1::runtime:2755dc322c8dbb64760145d6403d14432af527bf4dd3cf03713aae10e0f8b552
--
2023-07-13T05:49:25.501Z	undefined	ERROR	Uncaught Exception     {
    "errorType": "TypeError",
    "errorMessage": "Class extends value undefined is not a constructor or null",
    "stack": [
        "TypeError: Class extends value undefined is not a constructor or null",
        "    at ../../aws-cdk-lib/core/lib/cfn-condition.ts (/var/task/index.js:796267:5)",
        "    at __init (/var/task/index.js:9:56)",
        "    at ../../aws-cdk-lib/core/lib/private/metadata-resource.ts (/var/task/index.js:807546:5)",
        "    at __init (/var/task/index.js:9:56)",
        "    at ../../aws-cdk-lib/core/lib/private/synthesis.ts (/var/task/index.js:814923:5)",
        "    at __init (/var/task/index.js:9:56)",
        "    at ../../aws-cdk-lib/core/lib/app.ts (/var/task/index.js:814951:5)",
        "    at __init (/var/task/index.js:9:56)",
        "    at ../../aws-cdk-lib/core/lib/stack.ts (/var/task/index.js:816555:5)",
        "    at __init (/var/task/index.js:9:56)"
    ]
}
START RequestId: b6da27f5-d7ff-4f76-807b-c7f5d1f02d1f Version: $LATEST
Unknown application error occurredRuntime.Unknown
END RequestId: b6da27f5-d7ff-4f76-807b-c7f5d1f02d1f
REPORT RequestId: b6da27f5-d7ff-4f76-807b-c7f5d1f02d1f	Duration: 13083.91 ms	Billed Duration: 13084 ms	Memory Size: 128 MB	Max Memory Used: 128 MB
```

## Solution

Extract the SDK v2 to v3 features into a new private package that can be bundled safely.
Also required changes to the `aws-custom-resource` v3 handler so it can used the shared code.
To make sure that the bundled files are free of start-up errors, I have added them into a post build script.

## Additional changes

**Update to Encode/Decode logic**
All parameters passed to a Custom Resource will be converted to string when passed to the Lambda Function handler. 
This is a feature/limitation by CloudFormation.
The previous implementation supported special handling for boolean values via a magic string.
However with the SDK v3 parameter types on API Calls are more strictly enforced, e.g. we can't pass a string anymore when a number is expected.
Therefore the encoding/decoding logic has been updated to indiscriminately encode _all_ parameters with `JSON.stringify()` and reverse the operation inside the assertions provider.

**Lambda Invoke Payload**
Withe the SDK v3, the type of the Payload returned from a Lambda Invoke operation is now a Buffer.
This makes sense from an SDK perspective since the returned payload might be a binary.
However assertions can only deal with JSON payloads, so we attempt to convert and parse the payload into a JSON object.
If that fails it stays unchanged.

## Acknowledgements 

Thanks @WinterYukky  for the initial investigation!

Closes aws#26359
Replaces aws#26360

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*