Allow password expiration handling

[guzman-raphael]

trafficstars

https://github.com/PyMySQL/PyMySQL/issues/572

Also, to be compatible with this approach, we will need to:

• Convert set_password logic from SET PASSWORD... to ALTER USER...
• If user password is indeed expired, that the first query that is run is like ALTER USER... to allow flow to update it.

[dimitri-yatsenko]

Let's start working toward feature parity with postgresql and verify that each feature would work equivalently with postgresql too.