Migrate some of the moodle postgres stuff to ansible

Testing with ansible on F18 64bit. Need to disable SELinux as well as get moodle installed. Moodle seems to create user/db for apache which already exist. Migrating these to ansible will be idempotent.

Note: there's still an issue with the postgres user authentication. sudo'ing as postgres still results in "Peer authentication failed for user 'postgres'"