Support readonly connections #338
Description
tursodatabase/libsql-js#24 asked for readonly support in the JS client.
That issue was marked as blocked on tursodatabase/libsql#344.
tursodatabase/libsql#347 was opened to address 344, then closed in favor of tursodatabase/libsql@befd735.
expandConfig doesn't support a mode=ro option, so this library prevents its use.
I'm happy to contribute, review, QA, or help in any way I can.