VID-1784 Script that can be run to update Video: links

My concern with RLIKE/REGEXP was that it's not multi-byte safe.  However, the REGEX syntax is much cleaner and the worst that would happen is that we check a few extra pages on some wikis.

Also there are a *lot* of extensions (e.g. .svg, .pdf, ...) so I was just trying to cover a few major ones, not be completest (its not the end of the world if we scan a wrong page).  I think adding .jpeg makes sense.