guardian 2.0: suggested cosmetic changes

I did the following:

- Rearranged the fields on 'guardian.cgi' a bit - in a (hopefully) logical manner,
  so that they don't need so much room.
- Added some translation-strings and explanations to (revised) 'guardian.cgi'.
- Added missing language string(s), deleted obsolete.
- Deleted all guardian entries from standard language files in
  '/var/ipfire/langs'-directory.
- Added (upgraded) addon-specific language files to '/var/ipfire/addon-lang'-directory.

I hope, I didn't forget something...

Best,
Matthias

Signed-off-by: Matthias Fischer <matthias.fischer@ipfire.org>
Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>