[Jobs] --sync-down execution log support for managed jobs

[KeplerC]

This aims to resolve #4056 for managed jobs, we should have a flag --sync-down that download the logs to local machine.

Tested (run the relevant ones):

• Code formatting: bash format.sh
• manually tested

sky jobs logs --controller 7 --sync-down
sky jobs logs 7 --sync-down
sky jobs logs --name minimal --sync-down # download all of the job_ids using the same name
sky jobs logs --name minimal 7 --sync-down  #  error as expected 

• smoke tests

pytest tests/test_smoke.py::test_managed_jobs_logs_sync_down

[Michaelvll]

Thanks @KeplerC! Left several comments below : )

[Michaelvll]

Thanks @KeplerC! Left several comments : ) Also, we should add a smoke test for the newly added functionality

[cg505]

Looking pretty good now, left some relatively minor comments.
Also, please address the lint failures!

[cg505]

thanks for the changes, looks good to me!