Allow using sqlite extensions during comptime verification

[Suya1671]

Is your feature request related to a problem? Please describe.
I'm trying to use the uuid extension for the uuid_blob() function in sqlite. However, this errors out comptime verification since it doesn't load any extensions by default, nor is there a way to enable/add extensions at compile time.

Describe the solution you'd like
Some way to configure loading extensions during compile-time query checks. One way is to add query params to the DATABASE_URL (and also load the extensions at runtime as well), which would look something like sqlite://database.db?extension=uuid&extension=vsv

Describe alternatives you've considered
Compile sqlite with the extensions enabled by default

Additional context
seems that there were plans to do something like this in #1460 (comment)

[abonander]

This can be built on top of #3383 when it's merged. Something like:

[drivers.sqlite]
load-extensions = ["uuid", "vsv"]

[djarb]

That would be great! Being unable to use SQLite extensions in migrations just became a big problem for me. When using Spatialite, you have to be able to call Spatialite functions to create and delete spatial tables and build spatial indexes.

[areleu]

That would be great! Being unable to use SQLite extensions in migrations just became a big problem for me. When using Spatialite, you have to be able to call Spatialite functions to create and delete spatial tables and build spatial indexes.

I am currently facing the same issue right now, have you a work-around?

[djarb]

I found a partial workaround for the trouble with the migrations, but if you get past that you hit a hard stop with the compile-time checking. A way to tell SQLx to load extensions across the board is the correct solution.

My current plan is to devote time this week to implementing #3330 (comment) and submitting a pull request.