Add implementation for get fine-tuning jobs

[liron-l]

Describe the change Add missing implementation for GET /fine_tuning/jobs

Describe your solution Implemented the method as described in the API specification (consistent with other APIs)

Tests Added UTs and verified against endpoint

Issue: #574

[liron-l]

@sashabaranov will appreciate your review

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (515de02) 98.35% compared to head (b48c278) 98.16%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #575      +/-   ##
==========================================
- Coverage   98.35%   98.16%   -0.19%     
==========================================
  Files          24       24              
  Lines        1276     1310      +34     
==========================================
+ Hits         1255     1286      +31     
- Misses         15       17       +2     
- Partials        6        7       +1     

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[liron-l]

@sashabaranov will appreciate your review

[liron-l]

@sashabaranov Can't really verify this code