accounts-daemon service, fix gnome-shell, add libgnomekbd, musicbrainz5, sushi, gnome-contacts

[lucabrunox]

For some reason, gnome-shell worked out without gnome-settings-daemon gschemas on my system. After a garbage collect + rebuild, it didn't work anymore. Turned out it was missing gschemas dependency.
The accounts-daemon is used for knowing some user information in gnome-shell, however we should forbid changing accounts from gnome-control-center user-accounts.

[lucabrunox]

Updated. Added libgnomekbd.

[lucabrunox]

Added gnome-system-monitor, it's missing from #247 but it's in gnome core.

[lucabrunox]

added musicbrainz5 and gnome sushi

[lucabrunox]

added gnome-contacts, moved accountservce to services/desktops and sushi and eds to services/desktops/gnome3

[lucabrunox]

Added telepathy-mission-control dbus service

[lucabrunox]

Fix file-roller

[lucabrunox]

Added at-spi2-core service to nixos, for the a11y dbus name.

[lucabrunox]

Wrapped evolution-calendar-factory and gnome-contacts-search-provider. Removed desktop/gnome-dictionary. Added environment.gnome3.excludePackages.
I'm in doubt on whether the difference function should stay in lib/lists.nix or in gnome3.nix for now.

at-spi2-core spits this warning at startup, probably because it starts before gnome-session, and the service has no activation: org.a11y.atspi.Registry[11663]: ** (at-spi2-registryd:11666): WARNING **: Failed to register client: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.gnome.SessionManager was not provided by any .service files

So far this is the only noteworthy warning in the logs.

[domenkozar]

I tested it inside a virtualbox vm. I'll downgrade 3.12 apps, otherwise it looks good. I have a bunch of bugs that don't appear to you, we'll have to boil down those in near future.