Host a summit.openstack.org redirect on static

This provides a hollow "summit.openstack.org" vhost as a permanent
redirect to the openstack.org/summit site. As the summit schedule site
is no longer maintained, this ensures browser traffic goes somewhere
with helpful details about the summit rather than just timing out.

Change-Id: I5007214e69f8656981b6d173a0c6aa38be464fba