Separate the implementation of the SpatialJoin operation into a separate class

[Jonathan24680]

This makes the code cleaner by separating the boilerplate required as a subclass of Operation from the actual geometric calculations. It also makes the development much more convenient, as changing details in the implementation doesn't require the recompilation of the complete engine library.

[codecov]

Codecov Report

Attention: Patch coverage is 92.62295% with 9 lines in your changes missing coverage. Please review.

Project coverage is 88.47%. Comparing base (4acbca3) to head (4dd021d).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/engine/SpatialJoinAlgorithms.cpp	91.81%	2 Missing and 7 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1552      +/-   ##
==========================================
- Coverage   88.47%   88.47%   -0.01%     
==========================================
  Files         363      364       +1     
  Lines       27533    27534       +1     
  Branches     3714     3714              
==========================================
  Hits        24361    24361              
  Misses       1940     1940              
- Partials     1232     1233       +1     

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[sparql-conformance]

Conformance check passed ✅

No test result changes.

Details: https://qlever.cs.uni-freiburg.de/sparql-conformance-ui?cur=4dd021d421d05de4493c50f1879cfd2e585272b0&prev=4acbca3e3c9e024bbda82ad701b395441f7003e2

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud