Use better, less technical, and more consistent strings for name, comment, and GHNS button

Summary:
Change the KCM's name and comment to match one another and be less technical.

Also Implement consistent text format as decided on in T9941.

Test Plan: {F6372988}

Reviewers: #plasma, #vdg, apol

Reviewed By: apol

Subscribers: apol, plasma-devel

Tags: #plasma

Maniphest Tasks: T9941

Differential Revision: https://phabricator.kde.org/D16502