Add support for sqlite database

[pythongosssss]

Cut down version of #8432, to just contain the database setup code.

[bigcat88]

Suggestions:

1. Use WAL mode from start in case the database is SQLite
2. Use async from start to not rewrite code in future (even for SQLite)

Some code can be taken from here:

https://github.com/Visionatrix/Visionatrix/blob/ea4caf0a30f0a0c5a21d440be802cd2e624ffcf3/visionatrix/database.py#L210-L243

[bigcat88]

Also It would be great to be able to turn off the default database entirely - or better yet, to introduce a set of well-defined asynchronous persistence interfaces. That way, anyone building on ComfyUI (or simply wanting to swap in a different database backend) could implement those interfaces and have their chosen storage engine used transparently.
Moreover, a plugin‐based system for this feature feels much more in line with ComfyUI’s modular design; in its current form the PR seems geared more toward a Comfy-Desktop design. (I may be off-base here, as I haven’t seen all of the internal discussion)

[webfiltered]

or simply wanting to swap in a different database backend

Is there an issue with the current ORM impl. that would prevent this? Adding a custom abstraction layer feels pretty impractical to maintain, at present.

[bigcat88]

Is there an issue with the current ORM impl. that would prevent this? Adding a custom abstraction layer feels pretty impractical to maintain, at present.

As far as I know - no, you are absolutely right about not having to build an additional layer over SqlAlchemy. I probably didn't describe it quite accurately. By backends I meant SqlAlchemy engines, they are called backends in some places.

[webfiltered]

Do we need the ^sqlite:/// check? I assume the ORM will have an appropriate fit if it's misconfigured.

@bigcat88 Hadn't noticed this - disregard my earlier comment!

[github-actions]

(Automated Bot Message) CI Tests are running, you can view the results at https://ci.comfy.org/?branch=8444%2Fmerge

[webfiltered]

n.b. Merged as-is to unblock work, and flagged for follow-up / testing regarding allowing other DBs.