Deprecate param/version.py

[maximlt]

We recently archived autover but I completely forgot the implementation actually used across HoloViz lives is in param/version.py.

A few packages still depend on it but I don't see that as a blocker, those still active will need to migrate to an alternative solution (e.g. setuptools-scm) like we did recently for other packages. Other potential users of param/version.py are also highly encouraged to migrate immediately:

• jupyter-panel-proxy
• pyct
• earthsim
• nbsite
• nbsmoke