More generally support python in Multipy

[PaliC]

Currently, we only truly support python 3.8.6 for multipy/runtime and 3.7-3.9 for multipy.package. If we want general availability/ ease of use, we should not constrain users like this, but rather make these tools more available for users who want features of python above version 3.7.

Support more python versions in multipy/runtime

• Add explicit python 3.7, 3.9, and 3.10 support to multipy/runtime #95
• Using pyenv to dynamically link to python in multipy/runtime #97
• Add unit testing for multiple python versions in multipy/runtime #98

Support more python versions in multipy.package

• Support Python 3.10 #1