Clean up e2e Dockerfiles

[MrAlias]

As part of #1140, the Dockerfiles are clean up.

• Ensure the docker builds can be cached
• Unify the entrypoint of the e2e binary to be located in a Linux filesystem appropriate location
• Unify the Go application to be the main program that runs the testing application to prevent logic split when running
  • Update the kafka e2e test to call the Kafka setup script from the Go program