Rationalise model_id requirements in SentenceTransformerModel

[Jebq]

Description

This PR is mainly intended at removing the requirements for model_id arg when serializing a SentenceTransformerModel (both torch and onnx).
It also adds an argument in make_model_config_json to allow an user to provide a path where the json should be saved.

Issues Resolved

#323

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[codecov]

Codecov Report

Attention: Patch coverage is 85.71429% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 91.54%. Comparing base (5bfb6fb) to head (c58e75b).
Report is 1 commits behind head on main.

❗ Current head c58e75b differs from pull request most recent head 12e6351. Consider uploading reports for the commit 12e6351 to get more accurate results

Files	Patch %	Lines
...search_py_ml/ml_models/sentencetransformermodel.py	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #381      +/-   ##
==========================================
+ Coverage   91.53%   91.54%   +0.01%     
==========================================
  Files          42       42              
  Lines        4395     4401       +6     
==========================================
+ Hits         4023     4029       +6     
  Misses        372      372              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.