* allow a specific set of credentials
* reject a certain type of credentials
* deny password that can be easily cracked
* enforce use of an expiration date with a minimum of day for a password
* define a password reuse policy
* define the number of authentication failure allowed before a user is banned
* define a delay on authentication failures
* force users to change their password after first login
* throw a warning N days before when the password user is about to expire

- Fix error cannot change data type of view column "roleid" from oid to regrole.
- Add missing upgrade SQL file from 4.3 to 4.4.
- Fix error when the user want to modify his password and
credcheck.password_valid_until option is set.  As we modify
the VALID UNTIL clause it will generate an error message when
the user changes his password:
     Only roles with the CREATEROLE attribute and the ADMIN
     option on role "..." may alter this role.
- Set the tzp argument in timestamp2tm() call to apply timezone to converted
timestamp.