🚸 Allow creating circuits from compound operations

[burgholzer]

Description

This PR adds functionality to construct circuits from compound operations.
In the process, it also improves the QASM dumping functionality by making it const.
Last, but not least, it refactors the corresponding IO tests to use more convenient interfaces that are now available.

Fixes #600

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 92.1%. Comparing base (bcb8371) to head (ace3312).
Report is 104 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #690   +/-   ##
=====================================
  Coverage   92.1%   92.1%           
=====================================
  Files        125     125           
  Lines      13780   13790   +10     
  Branches    2153    2154    +1     
=====================================
+ Hits       12692   12704   +12     
+ Misses      1088    1086    -2     

Flag	Coverage Δ
cpp	91.8% <100.0%> (+<0.1%)	⬆️
python	99.7% <ø> (ø)

Files with missing lines	Coverage Δ
include/mqt-core/ir/QuantumComputation.hpp	91.9% <100.0%> (-0.6%)	⬇️
src/ir/Permutation.cpp	100.0% <100.0%> (ø)
src/ir/QuantumComputation.cpp	85.0% <100.0%> (+0.6%)	⬆️