Scripts/Naxxramas: Rework of Gluth

1) Gluth should be able to eat zombies close to him, one at the time, during the whole fight.
2) Gluth should be able to eat zombies at an accelerated rate after each Decimate.
3) The zombies should put the "Infected Wound" debuff on their auto-attack targets.
4) Zombies should have a normal threat table before decimate and should loose all kind of aggro behavior and walk toward Gluth after decimate.
5) Gluth shouldn't be affected by the decimate damage.
6) Newly poped zombies should have all players in their aggro list as soon as they spawn. So far, they were not moving and were only aggroed by proximity.
7) and several minor fixes (emotes, useless data in db).

src/server/game/Spells/SpellEffects.cpp

@@ -3359,16 +3359,6 @@ void Spell::EffectScriptEffect(SpellEffIndex effIndex)
                     m_caster->CastSpell(unitTarget, 22682, true);
                     return;
                 }
-                // Decimate
-                case 28374:
-                case 54426:
-                    if (unitTarget)
-                    {
-                        int32 decimateDamage = int32(unitTarget->GetHealth()) - int32(unitTarget->CountPctFromMaxHealth(5));
-                        if (decimateDamage > 0)
-                            m_caster->CastCustomSpell(28375, SPELLVALUE_BASE_POINT0, decimateDamage, unitTarget);
-                    }
-                    return;
                 // Mirren's Drinking Hat
                 case 29830:
                 {