Resolve SPI-1599 "Refresh python 3 pkg status"
Adds several packages which were previously only built for Python2 to the Python3 stacks. Some are updated in order to get a Python3 compatible version. Packages not added are primarily backports and mentioned here https://lcgdocs.web.cern.ch/lcgdocs/lcgreleases/python3/.
Part of SPI-1599