[Opcode] Implement SetFace opcode (#2167)

* Implement SetFace opcode

This implements the opcode that's used to update zone clients when a
client updates their face

* Use SetFace in #feature command

Add check for valid number

This adds the #feature eyes command which isn't in the illusion struct

common/emu_oplist.h

@@ -455,6 +455,7 @@ N(OP_ServerListResponse),
 N(OP_SessionReady),
 N(OP_SetChatServer),
 N(OP_SetChatServer2),
+N(OP_SetFace),
 N(OP_SetGroupTarget),
 N(OP_SetGuildMOTD),
 N(OP_SetGuildRank),