Enabling native AC support for Playerbot support.

[Celandriel]

There have been a few discussions about eliminating the need for a customized fork for Playerbots. @Takenbacon suggested I start this discussion as a way to track the effort in getting this done.

Ill summarize the changes below in order of impact.

1. Clientless Sessions - feat(Core): support headless sessions and add session-less APIs #27533 We need a headless flag on WorldSession
2. Path generation filters - Define NAV_GROUND_STEEP in terrain. unwalkable triangles, and
3. Hooks at bot-relevant points - feat(Core/Scripting): add SessionScript and hooks for server-driven characters #27531 Session update/logout/packet-sent
4. Module owned databases. feat(Core/Database): enable modules to own their database #27544 - Need to complete the effort started by 24525
5. feat(Core/Scripting): add OnPlayerCanMarkAccountOffline player hook #27599
6. Two DBC storeS - CharSections.dbc for generating valid bot appearances, EmotesTextSound.dbc and emotes. Not sure if there is a way around this. feat(Core/DBC): load CharSections and EmotesTextSound #27578
7. Handful of read only accessors. feat(Core/Misc): Add read-only module accessors #27579
8. Item link handling for bots. fix(Core/Chat): accept uppercase link colors and the 'found' tag #27580
9. misc utility calls fixes related to crashes. fix(Core/Item): null-owner guard in CheckSoulboundTradeExpire #27528, fix(Core/Creature): populate spawnId when saving creatures to DB #27532
   fix(Shared/DBC): keep DBC string when DB override column is empty #27581
   feat(Core/Deps): require Boost.Thread alongside the other Boost components #27584
   fix(Core/Database): allow reopening a DatabaseWorkerPool after a failed Open() #27585

[TheSCREWEDSoftware]

Happy to see since our last talk that a bunch of PRs have been made and merged!

[Celandriel]

Yup! The only thing that is really missing at this point is some pathfinding and map changes that I need to confirm are needed before doing the PR.