Switch from cloudpathlib to universal_pathlib

[remi-braun]

universal_pathlib is fsspec-based and manages more usecases (such as URLs) than cloudpathlib.
It would therefore be useful to switch from cloudpathlib to universal_pathlib when this library will be more stable (and comes with a proper documentation)

However this is a big change, so do it only for 2.0 verison.

In the meantime, prepare the code for the switch with:

• Creating an alias for AnyPath
• Don't import cloudpathlib outside of functions