Adding command line interfaces and entry points

[caitlinadams]

This PR introduces major restructuring to move configuration options and hardcoded filepaths out of core functions and into configuration files which can be taken via command line arguments. The key changes are:

• Adding a cli module and updating the pyproject.toml file to use functions from here as entry points
• Creating cli functions that allow a user to find S1 files on NCI based on the file id, run pyrosar+GAMMA processing on a scene, or submit a scene for processing to the NCI queue
• Removing hardcoded paths in modules, instead taking parameters that can be set on the command line or a configuration file
• Removing unused functions after restructure

[caitlinadams]

Noting that many files still have hard-coded paths and environment variables.

The biggest issue is for running the submission cli, which calls out to sar_antarctica/nci/submission/pyrosar_gamma/submit_job.py -- this currently has a hard-coded section for starting my personal development micromamba environment. This needs to be configurable (and eventually default to the NCI module) to allow multiple developers to submit jobs with development code.