ts_project_workers should expose a way to find the logs of the worker

[bhavitsharma]

Logging is not straightforward in worker mode since Bazel's protocol uses stdin/out for communication. However, we should expose a method to add logs to a file that we can inspect. Note that this is different from the compiler host's log which should be called using host.trace?

[thesayyn]

related to #189. We'd like to add this capability simply by using bazel's worker verbose flag.

[thesayyn]

fixed by #264