When a helm chart index has download URLs on a different host than the
remote's base URL (e.g. charts hosted on intel.github.io but downloads
on github.com), the URL rewriting would produce broken proxy URLs.
Now URLs with a different host are left as-is so helm downloads
directly from the source. Same-host URLs are still rewritten through
the proxy as before.
Also fixes the route prefix to use /local/ for local members.
unkinben