♻️🎨 Code cleanup and refactors

[burgholzer]

Description

Starting the year with some obligatory code cleanup and refactors.
The individual commits and the commit messages should more or less convey the bigger changes.
For the most part, it's really all about defining clearer interfaces and following some new clang-tidy suggestions.

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

Attention: Patch coverage is 90.95689% with 86 lines in your changes missing coverage. Please review.

Project coverage is 92.0%. Comparing base (2404c85) to head (c381adb).
Report is 12 commits behind head on main.

Files with missing lines	Patch %	Lines
src/ir/QuantumComputation.cpp	91.0%	27 Missing ⚠️
...c/ir/parsers/qasm3_parser/passes/ConstEvalPass.cpp	0.0%	16 Missing ⚠️
src/ir/operations/SymbolicOperation.cpp	56.0%	11 Missing ⚠️
include/mqt-core/dd/Operations.hpp	79.4%	8 Missing ⚠️
src/ir/operations/ClassicControlledOperation.cpp	86.5%	7 Missing ⚠️
src/algorithms/QPE.cpp	94.0%	6 Missing ⚠️
src/algorithms/Grover.cpp	92.1%	4 Missing ⚠️
include/mqt-core/ir/operations/AodOperation.hpp	0.0%	2 Missing ⚠️
include/mqt-core/ir/parsers/qasm3_parser/Types.hpp	0.0%	1 Missing ⚠️
...e/ir/parsers/qasm3_parser/passes/ConstEvalPass.hpp	0.0%	1 Missing ⚠️
... and 3 more

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #798     +/-   ##
=======================================
- Coverage   92.2%   92.0%   -0.3%     
=======================================
  Files        125     123      -2     
  Lines      13760   13776     +16     
  Branches    2167    2153     -14     
=======================================
- Hits       12697   12684     -13     
- Misses      1063    1092     +29     

Flag	Coverage Δ
cpp	91.8% <90.9%> (-0.3%)	⬇️
python	99.7% <ø> (ø)

Files with missing lines	Coverage Δ
include/mqt-core/dd/Simulation.hpp	100.0% <100.0%> (ø)
include/mqt-core/ir/QuantumComputation.hpp	100.0% <100.0%> (+8.0%)	⬆️
...-core/ir/operations/ClassicControlledOperation.hpp	96.7% <100.0%> (-0.2%)	⬇️
...clude/mqt-core/ir/operations/CompoundOperation.hpp	100.0% <100.0%> (ø)
include/mqt-core/ir/operations/Control.hpp	100.0% <ø> (ø)
include/mqt-core/ir/operations/Expression.hpp	92.7% <100.0%> (ø)
...ude/mqt-core/ir/operations/NonUnitaryOperation.hpp	100.0% <ø> (ø)
include/mqt-core/ir/operations/Operation.hpp	79.0% <100.0%> (-1.0%)	⬇️
...clude/mqt-core/ir/operations/StandardOperation.hpp	100.0% <ø> (ø)
...clude/mqt-core/ir/operations/SymbolicOperation.hpp	100.0% <ø> (ø)
... and 28 more

... and 2 files with indirect coverage changes