feat: Add support for ATTACHing SQLite databases together

[peasee]

🗣 Description

• Moves SqliteConnectionPool creation into a factory, to make the setup call and await stack cleaner.
• Removes the ability to set factory parameter option keys in SqliteTableProviderFactory. Option keys are now set permanently.
• SqliteConnectionPoolFactory also now decides the push down strategy, based on the existence of attached databases or database mode.
• Adds support for attaching multiple SQLite databases together, for future federation support. These changes should permit querying any table for federation across any SQLite reader connection.