[submit] Optionally copy workflow outputs to local

[msto]

Summary

When waiting for termination, fglatch submit should permit copying a terminated workflow's outputs to local. This permits use of fglatch submit in combination with pytest-workflow for integration tests on the Latch backend.

Suggestions

• Add a --local-output-directory flag. The workflow execution output directory should be copied to this location (use Lpath)
• This flag should only be permitted when --wait-for-termination is specified.