Adopt sqlite extension loading

[rossta]

The sqlite3-ruby gem recently published an improvement to make it easier and more flexible to load extensions:

sparklemotion/sqlite3-ruby#586

Ruby modules for SQLite extensions should implement the interface:

interface _ExtensionSpecifier
  def to_path: () → String
end

A complementary change in Rails takes advantage of this interface to integrate the primary configuration file with the new sqlite3-ruby interface for extension loading:

rails/rails#53827

The gem template provided here already has a similar method:

def loadable_path

This PR updates sqlite3-ruby and database.yml to take advantage of the new feature. Joy of Rails currently uses two extensions: sqlite-ulid and sqlite-vec. Since these gems do no currently implement the expected interface, I’ve added adapter classes to lib/.

Side note: I have also opened a PR on a repo that would presumably add the feature to the sqlite-vec gem and other extensions by the same author: asg017/sqlite-dist#11