Add feature to allow PyMISP.add_object to not add duplicates.

[Rafiot]

It requires changes on MISP side, do not merge until the tests are passing.

[coveralls]

Coverage decreased (-0.03%) to 39.346% when pulling f806a88 on obj_break_on_duplicates into de6125a on main.

[codecov]

Codecov Report

Merging #683 (f806a88) into main (de6125a) will decrease coverage by 0.02%.
The diff coverage is 12.50%.

@@            Coverage Diff             @@
##             main     #683      +/-   ##
==========================================
- Coverage   39.39%   39.36%   -0.03%     
==========================================
  Files          40       40              
  Lines        8204     8210       +6     
==========================================
  Hits         3232     3232              
- Misses       4972     4978       +6     

Impacted Files	Coverage Δ
tests/testlive_comprehensive.py	0.00% <0.00%> (ø)
pymisp/api.py	12.42% <33.33%> (-0.01%)	⬇️

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[Rafiot]

Merged: c3d6c3c