Fix git repo rendering

[Chris Warburton]

We should render an index page, git2html, artemis and asv for each repo.
The projects/repos index should link to projects/repos/repo-name.html,
which should be a redirect to the repo's index page.

What we do with these depends on whether we're going for Web or IPFS:

Web should put everything in /git/repo-name, with the repo as
/git/repo-name.git, and projects/repos/repo-name.html redirecting to
/git/repo-name

IPFS should put everything in their own IPFS entry (INCLUDING the repo,
which should be *inside* the repo dir, next to asv, artemis, etc.),
publish to IPNS, and make redirects point to IPNS.