Improvements to sign up process (closes #228 and #251)

 - Added dedicated data policy page (should be static but never mind)
 - Added submission time and blank-field (honeypot) checks to signup
   process
 - Broken out signup data and validation to its own model
Merge pull request #253 from PonteIneptique/css-issue

Various issues, new functions and stuff
Abstract search summary and parameter templates and unify across
the portal and the admin, adding the ability to order portal searches.
Closes #241.
Merge pull request #256 from PonteIneptique/css-issue

Css issue
Merge pull request #258 from PonteIneptique/css-issue

Css issue and install.md improvement
Increase max-width of collapsed breadcrumbs so they are by default not collapsed