Redirects to web archives should be indexed appropriately.

[anjackson]

In ukwa/ukwa-pywb#95 a (broken) redirect to the web archive was causing problems. But self redirects cause other problems e.g. see ukwa/ukwa-pywb#72

• Ideally, redirects into UKWA should be filtered out before being added to the CDX index.
• Redirects to other web archives should ideally direct the user to those web archives.

It's not clear if either of these are particularly straightforward.