Rewrite journal GUI quest index

 - Use quest names as identifiers, not quest IDs. This ensures that quests with different IDs, but the same name (e.g. A2_4_MiloCaiusGone and A2_4_MiloGone) are merged properly, as they should.
 - Switch display from BookPage to MWList. Handles word-wrapping and scrolling properly.
 - Fixes a bug where the quest index would not be updated when opened.