Move homepage into server directory

It's all server rendered code
Move housing into experimental directory

It shouldn't appear linked anywhere, so rather than having to blacklist everywhere, just move it out of the main directory.
Remove old tx dashboards

These were generated earlier, but then removed from the list for later iterations of the generator, but did not have the files removed.
Update homepage template and css to include high volume dashboards and service groups
Update dashboard types for site activity and vehicle licensing

To allow better filtering of dashboards required to render the new homepage
Add flag to remove a dashboard from homepage list
Simplify collecton output so template is always passed raw data
Adjust borders on items in service list

Adds a bottom border to all li or similar
Merge pull request #451 from alphagov/feature/homepage

Feature/homepage