update: inertia benefit from caching + move from pkg_resources to importlib.metada

[m-rauen]

As stated in the setuptools page, using pkg_resources is deprecated in favor of importlib. Therefore, I took the initiative to change it.

I noticed that inertia moment can benefit from cache strategy and decided to implement it. Cache requires hashable objects and arrays/numpy arrays aren't. So, I decided to create a prototype of those arrays, make them hashable and introduce cache, while passing the same array to the function and not generating errors.

I also changed the jax callout, as it's already resolved in #713.