Enhance: optional notes field for mailing lists

It might be useful to allow installations to provide an optional notes field for mailing lists.

In particular, many of the ASF lists have changed names, so the complete history may be spread across several mailing lists. It would be useful to be able to document this somehow.

There would certainly be space for an Info icon on the screen, but for list name changes it would be useful to have the text on the screen itself; if there is more info than would fit nicely on the screen the text could be a link to the full description.

An alternative for the name changes would be to include backwards and forwards links (as relevant) in the Archive: menu. i.e. if the current list is a continuation of a previous list, then add a link to the previous incarnation at the end of the list. And vice versa.

The notes field could also be used to document the purpose of the list, as this is not always clear from the name. For example, the dev@community ASF list often gets postings which would be better directed elsewhere.

Start by tracing how mailing lists are configured and rendered on the screen, including the Archive: menu. Compare the proposed notes field, link, and previous/next-list alternatives before choosing a scope. Done should provide a clear way to document list purpose and name history for installations.

Written by the indexing model from the issue text.