Move PHPMyAdmin password definition to defaults

Fixes #161.
Change how monit is reloaded

Monit will check its config files before reloading.

Fixes #162.
Add 'debops.auth' as a dependency of other roles

This should prevent roles when required system groups are not present.
Alternative would be to make sure that each role creates required system
groups, but since there's at the moment small amount of groups, I think
this solution will suffice for now.

Fixes #163.
Merge pull request #170 from drybjed/bugfixes

Various bugfixes