Summary:
The Font Install KCM has a very dated layout. Thisd patch addresses some (but not all) of the aesthetic and usability deficiencies by doing the following:
- Eliminate the tools menu and relocate its two items elsewhere
- Move the GHNS button to the bottom-right corner, like every other KCM
- Put the {nav Scan for Duplicate Fonts...} action on the toolbar
- Change {nav Add...} into {nav Install from File...} to match the style of other KCMs

Test Plan: {F6375087}

Reviewers: #plasma, #vdg, davidedmundson

Reviewed By: #plasma, davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Maniphest Tasks: T9954

Differential Revision: https://phabricator.kde.org/D16536