Implementation of publish experiment feature and variable STAC catalog generation for each variable in the dataset

[TejasMorbagal]

This PR implements

1. variable STAC catalog generation for each variable in the dataset.
2. publish experiment cli and method

Note that 'gcmd_keyword_url' is expected as variable metadata if the variable in the dataset doesn't have a corresponding catalog already in OSC.

[codecov]

Codecov Report

Attention: Patch coverage is 77.61194% with 75 lines in your changes missing coverage. Please review.

Project coverage is 86.32%. Comparing base (c363d08) to head (5503cd8).
Report is 22 commits behind head on main.

Files with missing lines	Patch %	Lines
deep_code/tools/publish.py	60.97%	32 Missing ⚠️
deep_code/utils/dataset_stac_generator.py	47.36%	30 Missing ⚠️
deep_code/cli/publish.py	0.00%	7 Missing ⚠️
deep_code/utils/github_automation.py	33.33%	4 Missing ⚠️
deep_code/cli/main.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main       #3      +/-   ##
==========================================
- Coverage   90.82%   86.32%   -4.50%     
==========================================
  Files          13       17       +4     
  Lines         665      929     +264     
==========================================
+ Hits          604      802     +198     
- Misses         61      127      +66     

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[forman]

Overall nice work. Clean and comprehensive code.