Fixes #8668: Hide 'Server' kickstart repositories from enablement.

This also moves kickstart repositories to their own tab similar to
other 'types' and to make them easier to locate.
fixes #6637 - loosening url validation restrictions
Merge pull request #4867 from ehelms/fixes-8668

Fixes #8668: Hide 'Server' kickstart repositories from enablement.
Merge pull request #4871 from jlsherrill/6637

fixes #6637 - loosening url validation restrictions