Move Elynia's thorns attack animation from an AMLA definition to her unit types

There is no problem with having an initially-unused attack animation,
and it allows for cleaner code.
Expand instances of the DURATION_SCENARIO compatibility macro, and drop it
Shadow Master -> Chaos Emperor
Voice of Uria -> Uria

... Since the Voice of Uria is now an actual rank which was given to
Argan, as detailed in AtS.
Replace instances of MODIFY_UNIT with FACE_DIRECTION where appropriate