DB/Creature: Spawn Thalorien Dawnseeker's remains

Closes #11017
Core/Players: Fixed trainers still displaying profession skills after learning

Closes #8103
Core/Misc: Fix coverity analysis issues
Core: Fix typo in 316d9a5ce89b1a21a22b4ef038d9c76e91e0e948
Core/Dependencies: Upgrade to jemalloc-3.6.0
Core/Players: Fixed Death Knight starting First Aid skill max value
Core/Dependencies: Clean up recastnavigation folder

Remove old files from recastnavigation folder and update the structure to the same of https://github.com/memononen/recastnavigation/ to allow easier updates.
DB/Spells: Added all serverside spells for 3.3.5a
DB/Creature: Fix Kroshius text

By Rushor, closes #11801
Merge pull request #58 from TrinityCore/master

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