Scripts/Onyxia Lair: small rework

- fix crash on boss death
- avoid abusing during phase switch
- added better facing through trigger
- corrected some timers
- corrected inhabit type
mmh.... it's not actually the same thing If I call _JustDied()?
It will
-remove my summons without needing a summonlist
set boss state to done (right?)
Reset the events
isn't it?