Fixes #7489 - changed root password label to 'must' instead of 'should'
Fixes #7437: validation instead of PGError when host group title is exactly 256 characters
refs #7038 - use n_() for plural support, use Rails style length message
Fixes #7164: Cannot create a domain that starts or ends with '.'
Fixes #7450 - do not mark non-required fields

If validation is conditional we don't mark fields as required by
default. Also fixes disabling by override using :required option.