KDED is translated again
Rename the core's pot to kdeconnect-core.pot and make sure the library
loads the catalog when it's linked to.
Provide a separate translations file for all the plugins, together.
REVIEW: 118774
Ported using KDELibs4Support, for a smaller delta, so we can keep
developing on master until we decide not to.
At the moment, it builds and installs but tests don't pass because
of a QCA2 initialization problem I didn't manage to debug yet.
CCMAIL: kdeconnect@kde.org