DB/Quests: Fix Foolish Endeavors, closes #1880 closes #9849

Thanks to @dr-j for a major part of the work!

Also rename a file.
Core/Maps: Fixed Map::IsInWater returning true at any height above water
Core/Creatures

* Refactored setting movement flags into separate method
* Falling creatures are no longer treated as flying for movement flag setting purposes
Core/PacketIO: Send item create object blocks only to their owner
Update README
DB/Creature: Fix startup error
More organizing of sql/old, hooray!
Merge pull request #9983 from LeGuybrush/organize-

More organizing of sql/old, hooray!
DB/Quests: Fix Danger! Explosives!, closes #6850 closes #9458
Core/Scripts: Simplify spellscript from 1f785905d548257b56d83f180f3d8e94e8de0634
Core/Gossip: Revert unlearn and dual spec gossip stuff in c238cae7d0733c76ee844d81e7c959627e5d711b
Core/Spells: Fixed fishing broken in a recent commit