Allow to specify service to start from docker compose.

For now I've managed to select started services like this 

```
PropertyInfo finfo = typeof(DockerComposeCompositeService).GetProperty("Config", bindingFlags)!;

var config = (DockerComposeConfig)finfo.GetValue(svc);

config.Services = config.Services.ArrayAdd("myservice");

Can a fluent service management be added to the builder?
Thanks