3rd party repos policy: merge wiki material
At some point in the past, a more elaborate 3rd party repos
policy was approved and recorded on the Workstation wiki pages:
https://fedoraproject.org/wiki/Workstation/Third_party_software_Workstation_Guidelines
The wiki page contains some useful guidance and applies to all Fedora editions
and spins, so merging the content into the FESCo documentation makes the most
sense.
The previous version of the FESCo policy stated that 3rd party repos containing
free software must be approved by FESCo and Fedora Legal, whereas non-free
repos can be approved by working groups. The new version resolves this
inconsistency, to say that working groups can approve either type of repo.