Use androidx sqlite bindings internally

[simolus3]

This restructures our internal driver implementations to be aligned with cross-platform APIs from the androidx.sqlite:sqlite library, and removes all internal usages of SQLiter, SQLDelight and sqlite-jdbc:

• The :persistence project has been removed.
• The :dialect project has been removed.
• The :static-sqlite-driver project has been removed.

As a replacement, this adds the experimental SQLiteConnectionPool API in :core. That API has been designed to:

• express the assumption that the PowerSync SDK will be implemented ontop of a connection pool.
• make it easy to implement with our existing connection pool implementation.
• be a direct and low-level wrapper around SQLite connections (allowing our existing APIs to be implemented as wrappers).
• allow implementations based on Room and GRDB connection pools (the read() and write() methods correspond to useConnection in Room, see the Transactor API from Room for a comparison).

Since pools can now be implemented externally, there's a new (also marked as experimental) PowerSyncDatabase.opened method to open a PowerSync database ontop of those pools. The internal opening logic has also been refactored to call that method.

Since we're now using a BundledSQLiteDriver from androidx.sqlite, the platform-specific parts of the opening factory are greatly reduced. The only remaining platform-specific parts relate to loading the PowerSync core extension and finding a suitable default directory. The rest is now based in common.

In :core, the public interfaces like the cursor are then consistently implemented across the common underlying connection pool API.

I've also added a new API to PowerSyncDatabase to give out a temporary view to an underlying SQLiteConnection. This would give users full control over the statements to run, while still letting the PowerSync SDK taking care of connection management.

TODOs:

• Check Swift SDK still works with this.
• Check we're using the same paths as SQLiter by default