Core/Player: Implement a method to send out the Postmaster's item retrieval mails as it seems to be used in multiple places and also send disenchant roll result as a mail if the player's inventory is full
Merge pull request #12958 from Nyeriah/patch-ir

Core/Player: Implement a method to send out the Postmaster's item retrie...
Core/Battleground/AV: convert trinity_strings to proper creature_text

Closes #12861
DB/Creature: Remove startup error

Closes #12980
Scripts/Commands: Allow to set a custom duration to the Freeze command applied Aura

- Allow to set a default duration for the Freeze Aura in worldserver.conf
- Handle the .freeze and .unfreeze command custom effects through the Freeze AuraScript
- Make players able to eventually unfreeze by themselves since the aura will expire without someone having to use .unfreeze
- Make .freeze command usable with the following syntax:

      * .freeze (with a targeted player)
      * .freeze duration_in_seconds (with a targeted player)
      * .freeze playername duration (if duration is an invalid value it will be defaulted to the config one)
      * .freeze playername (in this case, duration will be defaulted to the config value)