Sync WCFSetup.css with default style

[TimWolla]

• [ ] Update WCFSetup.css
• [ ] Check if WCFSetup looks good.
• [ ] Update the inlined header.tpl stuff in rescueMode.tpl
  • [ ] Check rescueMode.tpl on mobile devices
  • [ ] Check if rescue mode looks good.
• [ ] Remove all links in WCFSetup and Rescue Mode.
  • Clicking such a link in WCFSetup will effectively abort the process.
  • In Rescue Mode the template should be as simple as possible as well and not give any interactive elements that are not required (specifically the logo link).

[dtdesign]

The setup CSS and HTML have been severely out-of-sync for a few versions already. We should revisit this in a future version and completely rewrite the CSS for it so that it no longer depends on the existing UI.