Update UNIX_USER on installation setup of crontab.

Fixes #974.
Add executable permissions to script
[Harrogate] basic cobrand
Open311: honour `variable` field in form display

Potentially addresses #42 and
https://github.com/mysociety/FixMyStreet-Commercial/issues/647
[Harrogate] custom form fields

Requires previous (generic) commit to prevent information only
categories (e.g. Dead animals message) from displaying a spurious
textbox.

Also support for sending thesecustom fields by email:

Requires a hook in RS::Problem method, as by default, only a restricted
number of hard-coded fields are send in the email.

(And the template language is pseudo-PHP so we can't simply pass in the
whole data-structure.)
[Harrogate] wordings and styles

 - auth and intro pages
 - wording of around page
 - Styling work with Mike
 - FAQ and footer tweaks
   https://github.com/mysociety/FixMyStreet-Commercial/issues/654
   https://github.com/mysociety/FixMyStreet-Commercial/issues/655
 - Extra spacing
   https://github.com/mysociety/FixMyStreet-Commercial/issues/656
 - Width of footer (override auto -> 100%)
 - style and logo tweaks
 - Logo/header same height on all pages (inc mappage)
 - Content spacing tweaks
 - Correct "Harrogate district" wording
   https://github.com/mysociety/FixMyStreet-Commercial/issues/658
 - Add extra disclaimer about reports fwd'd to NYCC