Migrate defunct ImageJ User & Developer Conference content

[ctrueden]

The imagejconf.tudor.lu site is defunct now, and imagejdocu.list.lu does not have all the previous content. Let's migrate all the content from those conferences to imagej.net.

We can pull it out of the Wayback Machine:

• https://web.archive.org/web/20210420081811/https://imagejconf.tudor.lu/

The area of imagej.net where this content would go is:

• https://imagej.net/events/conferences
• https://imagej.net/events/conference-2006
• https://imagej.net/events/conference-2008
• https://imagej.net/events/conference-2010
• https://imagej.net/events/conference-2012

The 2008 content appears to exist on imagejdocu, although it should be manually inspected and compared against the content scraped from Wayback Machine before migrating.