Implement simple media detail page

Implement simple media detail page

This patch creates a "homepage" for each media. The URL is
/u/<username>/m/<objID>.

On it we display the media and some details. It is ugly and lacking some
stuff but it works. The only thing left to do is to throw an 404 error
if the <username> and the media uploader don't correspond.

- Also create a user "home page" while at it. It is merely a place
  holder for now though.

- Link from the entries on the homepage, to the media pages, so we
actually find them.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>