port mouse settings from mpc-be

[adipose]

This is a work in progress. I didn't update the themed elements yet, but the basics work well enough for testing. We will have to decide about the following deficiencies:

1. No differentiation between mouse down and mouse up
2. Inability to use one mouse action for multiple commands (maybe a good thing)
3. Not porting the existing commands from the old table. Could be fixed.