In place union and concatenation in Python binding

[Adda0]

This PR adds in-place variants of concatenation and union to Python binding. Additionally, it adds a temporary deepcopy function for Python Nfa class. Proper deepcopy using Python copy.deepcopy() will come in a later PR.

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (1494bd4) 71.80% compared to head (60954c0) 71.82%.
Report is 18 commits behind head on devel.

❗ Current head 60954c0 differs from pull request most recent head 09a43aa. Consider uploading reports for the commit 09a43aa to get more accurate results

Files	Patch %	Lines
src/nfa/delta.cc	81.81%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##            devel     #369      +/-   ##
==========================================
+ Coverage   71.80%   71.82%   +0.01%     
==========================================
  Files          30       30              
  Lines        3643     3642       -1     
  Branches      836      834       -2     
==========================================
  Hits         2616     2616              
  Misses        735      735              
+ Partials      292      291       -1     

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

[jurajsic]

Looks good, just some weird sentences in comments