MT#6459 Fix peering contract and peer auth pref.

- Properly call localization functions on error when changing
peering contract.
- Properly handle preference update in case of empty value.

Reported by Marc Storck on spce-users.
MT#6443 Calculate dashboard costs correctly
MT#6461 Let admin rebrand reseller.

Reseller rebranding itself not yet there.
MT#6479 API: Allow resellers to access some funcs.
MT#6283 Add more query params to existing colls
MT#6497 API: get callforwards (simple)