Change `load_geometry` to default True

I like the fact that `load_geometry` defaults to True. Let's change it also in the other classes that already have functions like that

_Originally posted by @gonzalocasas in https://github.com/compas-dev/compas_fab/pull/406#discussion_r1543942964_

This might simplify some simple examples and use cases, however, we need to make sure we don't accidentally trigger a lot more testing code to be ran because several tests seem to be relying on the fact that this defaults to `False`.