Add a page for community sourced examples

[vrabbi]

As discussed in the June 1st community meeting, it would be great to have a page on the site with links to examples that are out there for cartographer.
It could contain examples such as the cartographer-catalog from TCE as a good example.
Ideally the page would have a simple edit button that would allow someone to open a PR directly and they could add the link to a repo and a short description of what the example includes.
This would allow showing the pluggability of cartographer as well as serve as a source of inspiration for many people on what they could do with cartographer in their own platforms.