gh-129928: Rework sqlite3 error helpers (#129929)

Add a helper for raising DB-API compatible exceptions based on the
result code of SQLite C APIs. Some APIs do not store the error indicator
on the database pointer, so we need to be able to deduce the DB-API
compatible exception directly from the error code.

- rename _pysqlite_seterror() as set_error_from_db()
- introduce set_error_from_code()