[ENHANCEMENT] Custom pre-death music loop & animation behavior

[anysad]

Briefly describe the issue(s) fixed.

• This PR aims to add an event dedicated to adding custom logic before the music and animation starts. As one of the devs (probably EliteMasterEric himself) put it:
  TODO: Make the behavior for playing Jeff's voicelines generic or un-hardcoded.
This will simplify the class and make it easier for mods to add death quotes.
• By utilizing this new event, this PR also softcodes Jeff's voicelines (aka Tankman in week 7). Just because it's convenient.
• And last but not least. eventn -> event 🙂

Include any relevant screenshots or videos.

• Just to put it out here, this event uses two parameters. The first one is whether the game over music should play in the first place, and the second parameter is the volume of said game over music.