Removes all legacy code that is not used.
Changes:

• mocks are now in root mock package to make it easier to test and find them
• all deposit, event and message handlers are exepected to be written in the package that uses core package
• config is removed and expected to be implemented by the relayer
• packages rearranged where it makes sense
• Proposal and Message moved to root package types and expected to be used by all implemented chains (format will be changed in the upcoming refactors)
• msgChan removed from being passed to listener and expected to be passed to specific handlers to facilitate future refactor of arbitrary messages between chains
• CLI removed
• logger and Opentelemetery moved to observability (waits for upcoming tracing union of it)

Description

Related Issue Or Context

Closes: #6

How Has This Been Tested? Testing details.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation

Checklist:

• I have commented my code, particularly in hard-to-understand areas.
• I have ensured that all acceptance criteria (or expected behavior) from issue are met
• I have updated the documentation locally and in chainbridge-docs.
• I have added tests to cover my changes.
• I have ensured that all the checks are passing and green, I've signed the CLA bot