Core/Transports: Fixed crashes caused by invalid leftover transport references

Closes #12282
Core/Spells: Fix Leader of the Pack

Broken with 6b430db910c2cffe49dc1049661c111f164f94f5 because we used the wrong spell...
Merge pull request #12291 from Unholychick/patch-lotp

Core/Spells: Fix Leader of the Pack
DB/SpellGroups: Fix a couple of runtime DB errors from f27821486b0c38e0f92bc719c997f3e9435d7c59
Update SpellAuraEffects.cpp

Cleanup. Already in spell scripts.
Merge pull request #12299 from SeTM/patch-1

Update SpellAuraEffects.cpp
Core/Spells fix 0442ff5c991c351cd6da3c04d1768f756d09fe22

Let it apply only to players
Core/Pets: Fixed pet power regeneration

Closes #12292
Merge pull request #12301 from Unholychick/patch-3

Core/Spells fix 0442ff5c991c351cd6da3c04d1768f756d09fe22
Scripts/Misc: Fixed training dummies not entering combat
Scripts/Icecrown Citadel: Fixed a possibility to start the encounter again if Tirion evades during outro RP

Closes #10060
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