MERGE THIS WITH MAIN RENAME rename moar types
Fix ContactManager introspection flow and signal connections
Don't check Connection.Requests interface as it is now mandatory

Connection.Interface.Requests is no longer given in the Interfaces
property of the Connection because it can always be assumed that it is
present.
Sync spec to 0.99.7
Client.Handler.HandleChannels -> HandleChannel

Made for auth-handler handling channels. This is the benchmark
Remove Channel.Interface.DTMF

Channel.I.DTMF has been removed and re-implemented into Content.I.DTMF
and Channel.T.Call. (fd.o #46443)
ChannelDispatchOperation.HandleWithTime -> HandleWith
Sync to telepathy-spec 0.99.8
Rename HandleType to EntityType