✨ switch to mqt-core Python package

[burgholzer]

Description

This PR switches the project to use the newly developed mqt-core Python package.
Any Python package build will only require the mqt-core package as a build and runtime dependency and won't have to rely on fetched version of mqt-core any more.
Any regular C++ build will still use the FetchContent CMake module.

The change brings a range of advantages:

• Uses the new load function of mqt-core that allows to load any supported circuit format as input and has better handling for Qiskit QuantumCircuit objects.
• Allows to directly feed QASM strings as inputs to the compilation methods
• Simplifies the interfaces of the QMAP Python bindings
• Allows OpenQASM3 as an input format.

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 95.65217% with 1 line in your changes missing coverage. Please review.

Project coverage is 90.3%. Comparing base (6b5d2d1) to head (dbaa9cb).

Files with missing lines	Patch %	Lines
src/mqt/qmap/__init__.py	93.7%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #418   +/-   ##
=====================================
  Coverage   90.3%   90.3%           
=====================================
  Files         90      90           
  Lines      10045   10047    +2     
  Branches    1711    1711           
=====================================
+ Hits        9075    9077    +2     
  Misses       970     970           

Flag	Coverage Δ
cpp	90.1% <ø> (ø)
python	93.5% <95.6%> (+<0.1%)	⬆️

Files with missing lines	Coverage Δ
src/mqt/qmap/clifford_synthesis.py	94.2% <100.0%> (-0.6%)	⬇️
src/mqt/qmap/compile.py	97.1% <100.0%> (+<0.1%)	⬆️
src/mqt/qmap/__init__.py	95.8% <93.7%> (+1.7%)	⬆️