Remove trainer_... fields from creature_template and move trainerType to DB

[FlagFlayer]

🍰 Pullrequest

Main changes:

• Remove deprecated trainer_... fields from creature_template (except for trainer_id, not all trainer_ids are sniffed).

• Move trainerType assignment to DB and evaluate based on sniffed values.

• Handle trainer gossip options via conditions in gossip_menu_option. All missing gossip options and conditions have been added and applied.

Miscellaneous

• Clean up deprecated code: "msg" field in IsTrainerOf and CanInteractWithBattleMaster (has no function)

How2Test

• Talk to a trainer. Trainer gossip option appears when the correct conditions are met.
• Use .learn all_trainer. It correctly teaches all available trainer spells.

Todo / Checklist

• Remove relevant fields from creature_template and replace code that is reliant on them
• Move trainerType assignment to DB (trainer greeting type)
• Adjust the Core to work with the new DB assignment
• Reimplement .learn all_trainer command in the new environment

[ratkosrb]

What happened with the Soothsaying fixes, did that implementation require these changes first?

[mserajnik]

What happened with the Soothsaying fixes, did that implementation require these changes first?

I think he just decided to split up the PR, see his comment here: #1705 (comment)

[FlagFlayer]

What happened with the Soothsaying fixes, did that implementation require these changes first?

They did not require this, but since this part of the fixes makes the trainer_spell column become completely empty I bundled these fixes with this change.

What I'm missing for the Soothsaying fixes is sniffs of the gossip submenus when going through the option "I would like to relearn my leatherworking focus", as well as the correct order of entries when talking to Book Soothsaying for Dummies and having both the leatherworking and the engineering options available. I haven't been able to get around to getting these sniffs, I hope someone else might be able to obtain them at some point.

[FlagFlayer]

Ready for merge