[#10929] Apply proxy pattern for logs and task queue

[wkurniawan07]

This is an extended part of #10929

We have used proxy pattern for third-party services like email and storage, but not yet on logs and task queue. With the proxy pattern we can allow mocking of the said third-party services and therefore unit-testing them in component tests.

• Applied proxy pattern for logs (new class LogsProcessor) and task queue
  • As a proof that the proxy pattern works, there is now CompileLogsActionTest
  • With this proxy pattern we can also tighten the architecture rules for the GCP-specific classes
• Standardized the way of how mocks are passed to action objects
  • This frees us from having to store method only used for testing in production code
• Simplified the implementation of MockFileStorage; in-memory storage of objects suffice and we don't really need actual I/O process

[t-cheepeng]

LGTM 💯

[rrtheonlyone]

LGTM 👍