We now use the telepathy interface when it's available, and fall back to
our custom dialog when it's not. This also makes the kdeconnect telepathy
connection manager be completely decoupled from the kdeconnect code.
CCMAIL: david@davidedmundson.co.uk
Makes it possible to specify the different properties sent at once,
rather than one by one as we used to do.
Also port whenever possible to the initializer-list syntax.
REVIEW: 128269