feat: allow URI filenames

[flavorjones]

See https://www.sqlite.org/uri.html

[flavorjones]

I think it might be better to not merge this -- the Open::URI bit can be passed where people want to pass a URI, and all the options available via URI are also available via the API.

What I really want is to be able to inject configuration options in a Rails app via the config/database.yml and so maybe it's better for me to do some work in the Rails sqlite3 adapter instead.

[flavorjones]

Since what I really want is to be able to inject behavior into the database of a Rails app via the database config, I'm going to shift focus to the sqlite adapter.

[flavorjones]

Hrm, reopening. It's hard to set just this one Open::URI bit from Rails for each connection because of how the database configs are passed-through to SQLite3::Database#initialize.

[flavorjones]

FWIW, it looks like the major distros compile with -DSQLITE_USE_URI=1, also (e.g. debian has compiled with it since 2019 / 3.27.1-1).

[tenderlove]

Ah, I didn't realize this was a feature natively supported by SQLite. Yes, we should do this.