Adding code guidelines

[martin-gaievski]

Description

There are no code guidelines for the repo, this slows down new contributors and add cycles during code reviews.

Check List

• All tests pass
• Commits are signed as 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

All modified and coverable lines are covered by tests ✅

Project coverage is 81.64%. Comparing base (628cb64) to head (14ff4f4).

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #502      +/-   ##
============================================
- Coverage     81.72%   81.64%   -0.09%     
+ Complexity     2511     1253    -1258     
============================================
  Files           190       95      -95     
  Lines          8564     4282    -4282     
  Branches       1436      718     -718     
============================================
- Hits           6999     3496    -3503     
+ Misses         1010      507     -503     
+ Partials        555      279     -276     

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[jmazanec15]

@martin-gaievski Can we update table of contents on dev guide as well?

[yuye-aws]

Hi @martin-gaievski ! Are you still taking care of this PR? Why this is still draft?

[martin-gaievski]

@yuye-aws resumed work on this PR, feel free to leave comments

[vibrantvarun]

@martin-gaievski Can we resurrect this PR ?

[martin-gaievski]

@martin-gaievski Can we resurrect this PR ?

yup, we can for sure, rebased it on latest main

[martin-gaievski]

BWC are failing, looks like ml-commons related problem:

https://github.com/opensearch-project/neural-search/actions/runs/12998883054/job/36253263991?pr=502#step:4:409

    org.opensearch.client.ResponseException: method [POST], host [http://[::1]:39469], URI [/neuralsearch-bwc-testsparseencodingprocessor_e2eflow/_doc/1?refresh=true], status line [HTTP/1.1 500 Internal Server Error]
    {"error":{"root_cause":[{"type":"null_pointer_exception","reason":"Cannot invoke \"org.opensearch.ml.common.output.model.ModelTensorOutput.getMlModelOutputs()\" because \"modelTensorOutput\" is null"}],"type":"null_pointer_exception","reason":"Cannot invoke \"org.opensearch.ml.common.output.model.ModelTensorOutput.getMlModelOutputs()\" because \"modelTensorOutput\" is null"},"status":500}