Room-persistent Music Trigger

[maddie480]

The music trigger does have 2 options, music track and progression.
But when the player dies, it goes back to whatever set in that room, either the room properties, or trigger at spawn point.

This request is about adding a "Persistent" value to the music trigger, so when triggered, the music track and progression are changed and won't revert back.
Keep in mind, that if you transition rooms or trigger another "Persistent" music trigger, the affect of those is overwriting it.

Requested by orbittwz#2340 and Thegur90#8195