mysql: grant users ALL perms on their dbs, remove mysql-fixperms

mysql: grant users ALL perms on their dbs, remove mysql-fixperms

Users were not given DROP permissions at the database level since that
came with the risk of the user dropping their own database, with DROP
permissions for individual tables granted by mysql-fixperms. This
safeguard unfortunately breaks most software since installation and
migration scripts usually assume a database wide grant has been issued
and they can use SQL like "DROP TABLE ... IF EXISTS".

Given this reality, grant users ALL permissions to their
database. Regular backups are critical, and can mitigate the risk as
best as it can be.