Add support for two Darkshore quests 945 and 2118

Quest 945 (Therylune Escape) is already handled by a DB script but this is an escort quest and it should be handled by SD2.

Quest 2118 was broken and uncompletable due to a GO not being handled by core or SD2.

Some minor adjustements remain for both quests but are only cosmetic as the quest are fully completable.