📝 Extended documentation for simulators

[burgholzer]

Description

This PR updates the DDSIM documentation of all available simulators to show more of their usage and some examples.
Interestingly, this revealed that the CoTenGra mode for the simulation path framework was not working anymore, which was subsequently fixed.

Fixes #345

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: 1 lines in your changes are missing coverage. Please review.

Comparison is base (28db785) 92.9% compared to head (634dcd8) 92.9%.

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #347   +/-   ##
=====================================
  Coverage   92.9%   92.9%           
=====================================
  Files         35      35           
  Lines       2663    2663           
  Branches     345     345           
=====================================
  Hits        2474    2474           
  Misses       189     189           

Flag	Coverage Δ		*Carryforward flag
cpp	94.8% <ø> (ø)		Carriedforward from 0f8c8b9
python	87.7% <0.0%> (ø)

*This pull request uses carry forward flags. Click here to find out more.

Files	Coverage Δ
src/mqt/ddsim/pathqasmsimulator.py	50.9% <0.0%> (ø)

[burgholzer]

The method that codecov complains about is actually covered by the new docs additions here. The docs build just does not report any coverage to codecov.