Add RawParameter API to pass raw SQL parameters to the database directly

[LordMZTE]

This adds a low-level API to directly pass raw SQL parameters to a database. For the motivation of this, please see the below issue.

Closes #2333

[an-tao]

@LordMZTE Thanks for your patch, would you please add some tests to the db_test.cc ?

[LordMZTE]

Thanks for the feedback! I've added an extra test case using an integer passed as RawParameter for each DB for each API.