New labels for issues and related summary issues

[Edward K. Ream]

#1064 summarizes all labels.  It is pinned to each issue.

New labels

- #1399 summarizes the new HelpWanted label. I created this issue so it could also be pinned to the top of each issue page.

- The new MostImportant label lists what I think the most important next steps are for Leo.

- The new comm-bridge label lists all issues related to communication bridges between Leo and other IDE's.

Summary

There is considerable overlap between the new labels.

Please let me know if you are interested in any of the HelpWanted projects.

Edward