tensorpotential changed name

Not urgent, but I'll forget otherwise:

`tensorpotential` on PyPI refers to the [grace-tensorpotential](https://github.com/ICAMS/grace-tensorpotential). Afaik, the version packaged here was never on PyPI. Likely we want a separate package for the 'new' tensorpotential just to avoid strange updates and allow users (i.e. us) to install both at the same time, even if that means the name is not the same as the pip package. This is not critical and I can look it at a later time.

Start by reviewing the tensorpotential feedstock and the linked grace-tensorpotential package on PyPI and GitHub. Clarify the intended new package name and how both packages should be installable together; the work is done when the naming avoids conflicting updates and matches the agreed packaging plan.

Written by the indexing model from the issue text.