Core/Players: Set fist weapon skill value equal to current unarmed skill when learning fist weapons for the first time
Scripts/ICC: fixed Festergut Malleable Goo (thx @ManuFe)

Closes #12023
Scripts/ICC: Summon Sealed Chest quest npc's upon the Lich King's Death

TODO: template updates for these npcs and gossips

Closes #10554
Closes #12591 (PR)

Signed-off-by: DDuarte <dnpd.dd@gmail.com>