This PR implements missing raw WAL API from LibSQL for future use for
offline-sync feature:
1. `wal_insert_begin` - begin WAL session by opening WAL read/write
transaction
2. `wal_insert_end` - finish WAL session by closing WAL transaction
opened by `wal_insert_begin` call
3. `wal_insert_frame` - insert frame `frame_no` with raw content `frame`
(WAL frame included)
For now any schema changes will not be reflected after
`wal_insert_frame` because `turso-db` do not re-parse schema without
need. I will fix this in follow up PR.
Reviewed-by: Pekka Enberg <penberg@iki.fi>
Closes#2231