Implement a Jukebox mode

[nilp0inter]

Is your feature request related to a problem? Please describe.
I'd like to run a list of demo's or arcades in attract mode as a short of "jukebox"

Describe the solution you'd like

• Ability to remote control what MiSTer is running
• Add cores/games/arcades to a playlist with a duration time for each one
• Play the list from the web interface

Describe alternatives you've considered
Implement only the remote control part and delegate the play sequence to another program.

Additional context
This feature was requested by @pividivi in #3 .