[FR] Distinguish between regex and exact match 404s + option to add regex matched 404s as exact match redirect

[hiasl]

It would be a helpful feature if the list of matched 404s in the Dashboard would show / know if it was handled by a regex match or an exact match. regex matched 404s should still offer the + button to create a new exact match out of it.

why?

• we currently work on a a multisite setup with different languages (we have 6) with each language having some topic startpages inside
• When we launch we want to create regex redirects for all old language urls to the language startpages in the new website. Maybe some more regex redirects for the startpages
• During the first months we would like to add specific exact match redirects for the most requested 404s within each language / topics while keeping the regex redirects to cover the rest of the 404s

in addition to #61 we could then have an additional filter for "regex handled" 404s