Add media status icons

Summary:
This is used to show the state of a media playing process.

These icons are introduced to distinguish the state from the action of
triggering the state.

Reviewers: Plasma, Frameworks, VDG, andreask, ngraham

Reviewed By: Frameworks, VDG, andreask, ngraham

Subscribers: ngraham

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D11054