refactor consistency check, improve performance

[FabianHofmann]

• Code changes are sufficiently documented; i.e. new functions contain docstrings and further explanations may be given in doc.
• Unit tests for new features were added (if applicable).
• Newly introduced dependencies are added to environment.yaml, environment_docs.yaml and setup.py (if applicable).
• A note for the release notes doc/release_notes.rst of the upcoming release is included.
• I consent to the release of this PR's code under the MIT license.

[p-glaum]

I was actually also working today on the consistency check because I encountered some infeasibilities and problems when solving my network due to nan values in the capital costs of n.generators. I started implementing a feature within check_inconsistency to check automatically before solving a network if there could be any issues which could occur because of nan values. Maybe we could also implement it in this PR or do another one. What do you think?
https://github.com/p-glaum/PyPSA/tree/update_consistency_check

[fneum]

@p-glaum separate Pr Based on this are would be good