Support user authentication extension

[simolus3]

Originally suggested by @rodydavis in simolus3/drift#2540.

Putting this on hold since, with the current build scripts, it's hard to create a customizable sqlite3 build for users. Once we're able to use Dart's native assets feature, we can allow users to opt-in to the extension and provide APIs for the exposed methods in this package.

[melWiss]

is there any plans for this?

[melWiss]

it would be extremely nice if we can add sqlite-vec or any other extension

[rodydavis]

For sqlite-vec that is possible already! I am working on a better example but here is one:

https://github.com/rodydavis/flutter_sqlite_document_search

Right now it uses the pre compiled binaries but working on a way to compile the extension with the flutter plugin template for ffi

[melWiss]

aaaa thank you very much, you're really a life saver

[rodydavis]

Also PR for sqlite-vec: asg017/sqlite-vec#119