Enhance type annotation, style and improve high_level.Model performance

[flferretti]

This pull request introduces minor enhancements in type annotations, code style, and performance. In particular, it:

• speeds up joint_names and link_names methods in the high_level.Model class, also bringing improvements to other internal methods that were dependent on them
• exposes jaxsim.oop.jax_tf wrapped function arguments type according to PEP 612
• updates style to the latest black version
• adds formatting support for Jupyter notebooks in CI

[diegoferigo]

LGTM, just a curiosity.

[diegoferigo]

For the records, as @flferretti noticed, the change we found in 086179a had the consequence to drastically reduce the time CI takes to run the tests, that is mainly JIT compilation time. The key here was replacing some logic computed during runtime (albeit simple) and used pretty often with direct access to a static attribute. Well done!