Viserio Cooldowns

Additional mythic assignments for Midnight Falls (L'ura).

Assignment page improved with a visual boss timeline for placing, dragging, and editing timers of a reminder row.

Pre-configure raid group positions from the Setup page. Arrange players into groups that NSRT uses for the in-game Arrange button.

Mythic Belo'ren boss timers verified with live data. Added Radiant Echoes, Voidlight Edict in P1, and Group Soak assignments.