Haul all the parameter name mapping/global/service/etc logic into one place.
Haul all the parameter name mapping/global/service/etc logic into one place.

The handling of settings between MC and AG (which each have their own
naming conventions and semantics) had grown organically and empirically
and needed to be re-worked (now that we have a better idea of what needs
to be done to get it right).

freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control,freedesktop-unofficial-mirror/telepathy__telepathy-mission-control