add [--dbuser=<value>] [--dbpass=<value>] parameters to core and plugin

[baldurmen]

I would like to restrict the regular database permissions of my Worpress installs to SELECT, INSERT, UPDATE, DELETE and manage all installs and updates via wp-cli with another database user with the full SELECT, INSERT, UPDATE, DELETE, CREATE, ALTER, DROP, INDEX SQL permissions.

The way I'm currently doing this is putting the site in maintenance, updating the permissions, updating the website, putting the old permissions back and then taking maintenance mode off and it's a PITA.

These options are already present for wp-cli db, but I'd like to see them for core and plugin too.

[swissspidy]

It's probably easier making these global parameters instead of adding them just to a few selected commands.