✨🏷️ Type stubs and strict mypy compliance

[burgholzer]

Description

This PR finally adds type stubs for the Python bindings of the DDSIM library. This was long overdue and finally allows us to mark the package as typed (i.e., compliant with PEP 561).
Furthermore, it turns on mypy's strict mode and addresses all corresponding warnings.
Typing-wise, this brings DDSIM in line with the other MQT tools.

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 97.61905% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 92.7%. Comparing base (3283ca5) to head (3753c08).

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #357     +/-   ##
=======================================
- Coverage   92.8%   92.7%   -0.1%     
=======================================
  Files         37      37             
  Lines       2559    2549     -10     
  Branches     310     309      -1     
=======================================
- Hits        2375    2365     -10     
  Misses       184     184             

Flag	Coverage Δ
cpp	94.7% <ø> (-0.1%)	⬇️
python	87.7% <97.6%> (-0.2%)	⬇️

Files	Coverage Δ
src/mqt/ddsim/deterministicnoisesimulator.py	100.0% <100.0%> (ø)
src/mqt/ddsim/header.py	100.0% <100.0%> (ø)
src/mqt/ddsim/job.py	59.3% <100.0%> (-7.3%)	⬇️
src/mqt/ddsim/primitives/__init__.py	100.0% <100.0%> (ø)
src/mqt/ddsim/primitives/estimator.py	93.2% <100.0%> (-0.2%)	⬇️
src/mqt/ddsim/primitives/sampler.py	100.0% <100.0%> (ø)
src/mqt/ddsim/provider.py	95.4% <100.0%> (ø)
src/mqt/ddsim/qasmsimulator.py	98.8% <100.0%> (ø)
src/mqt/ddsim/stochasticnoisesimulator.py	100.0% <100.0%> (ø)
src/mqt/ddsim/pathqasmsimulator.py	50.9% <50.0%> (ø)

... and 2 files with indirect coverage changes