Clean up inertia.py/mesh.py function arguments to match rest of API

[eric-heiden]

Functions from inertia.py, like def compute_sphere_inertia(density: float, r: float) have to match the format from the ModelBuilder using radius instead of r.

The h in def compute_capsule_inertia(density: float, r: float, h: float) should be the half height, not full height.
Same for the other functions.

Same for the functions in utils/mesh.py they all need to be consistent with all the other geometry namings and conventions.