Core/Packets: Updated some of the movement flag opcodes
Core/Creature: Implemented negative levels for creatures having -1 as expansion
Core/Packets: Fixed player movement speed change packets
Core/Units: Updated byte order in UNIT_FIELD_BYTES_0 - fixes weird models

Closes #13648
Core/DBC: Move sPhasesByGroupStore and access method to DB2Stores

DB2Stores were not loaded yet at the old position.
Core/Packets: Added SMSG_MOVE_TELEPORT, SMSG_MOVE_UPDATE_TELEPORT, CMSG_MOVE_TELEPORT_ACK packets
Core: Fixed an old merge mistake
Core/Misc: Fixed some of the Coverity defects
Core/Game: Fix several warnings about wrong data types
Core/Spells:
- some work on player starting spells and skills
- fixed basic spell learning
- fixed some spell related datastore loads
Merge branch 'Spells' of https://github.com/TrinityCore/TrinityCore into Spells
Merge branch '6.x' of https://github.com/TrinityCore/TrinityCore into Spells
Core/Spells:
- fixed special action buttons
- added all 6.0.3 player starting spells (needs a little cleanup after level based auto learning is done)
- added all 6.0.3 player starting actions