[9496] HomeBind fixes.

* Use area id instead zone id for home bind zone info as expected.
  This will for example proper show capital name in area himebinding for capital; tavern.
* Clarify that player create zone in fact is area (subzone)
* Implement SPELL_EFFECT_BIND for normal homebinding.
  Also support spell target position mode used in 53823/53821 spells
* Add Spell::EffectEmpty for mark spell effects that used but not expect any code in handler.
  Example weapon spells that used just as known spell markers for client.

Original patch idea inspirit by Sadikum patch suggestion.

src/game/Spell.cpp

@@ -2258,6 +2258,7 @@ void Spell::SetTargetMap(SpellEffectIndex effIndex, uint32 targetMode, UnitList&
                     }
                     break;
                 }
+                case SPELL_EFFECT_BIND:
                 case SPELL_EFFECT_RESURRECT:
                 case SPELL_EFFECT_PARRY:
                 case SPELL_EFFECT_BLOCK: