Backport freeradius and freeradius-python3

[Shaun S <dev@srsmith.co.uk>]

Hi,

Freeradius 3.0.20 is in bullseye, with experimental support for Python 3 via freeradius-python3.

Any chance of getting this into buster-backports? It would be great to start working with the python 3 module and finally deprecate python 2.

Thanks,

Shaun