✨ Stripping DDs of their identity

[burgholzer]

Description

This PR pulls in the changes from cda-tum/mqt-core#358, which considerably changes the way matrix decision diagrams are represented. Particularly, any node resembling the identity is now eliminated and only implicitly represented.
This further compacts the representation of quantum gates and makes the identity the most compact it can be---a single terminal node.
The overall performance improvements are still to be evaluated.

Checklist:

• The pull request only contains commits that are related to it.
• I have added appropriate tests and documentation.
• I have made sure that all CI jobs on GitHub pass.
• The pull request introduces no new warnings and follows the project's style guidelines.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.7%. Comparing base (cda4a73) to head (eadeaaf).

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #361   +/-   ##
=====================================
  Coverage   92.6%   92.7%           
=====================================
  Files         37      37           
  Lines       2549    2552    +3     
  Branches     309     310    +1     
=====================================
+ Hits        2362    2366    +4     
+ Misses       187     186    -1     

Flag	Coverage Δ
cpp	94.6% <100.0%> (+<0.1%)	⬆️
python	87.7% <ø> (ø)

Files	Coverage Δ
include/DeterministicNoiseSimulator.hpp	100.0% <100.0%> (ø)
src/HybridSchrodingerFeynmanSimulator.cpp	97.3% <100.0%> (+<0.1%)	⬆️
src/ShorFastSimulator.cpp	95.3% <100.0%> (ø)
src/ShorSimulator.cpp	96.1% <100.0%> (ø)

... and 1 file with indirect coverage changes