[Desktop and Panel] Add Super actions options per design

[WatchMkr]

Dropdown with:

• Open Launcher
• Open Workspaces
• Open Applications

Instead of "Let Super key" the label should be "Super key action" since left and right Super keys do the same thing.

[WillyWonksters]

It is helpful have distinct assignments for left and right super. Left super is used so frequently when switching between apps and workspaces, that I often accidentally open the launcher. I disable this, and now only open the launcher with right super.