Add translations for new memory sensors
Summary:
This adds the translated strings for the new Total, Available and
Allocated sensors.
Depends on D25305
Test Plan:
The sensor browser no longer shows the new sensors as "total", "available"
and "allocated" but "Total Memory" etc.
Reviewers: Plasma, davidedmundson
Reviewed By: Plasma, davidedmundson
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D25306