Publicly archive old SourceForge mailing lists

[arifthpe]

While reading old issues I encountered a link to the old Chapel mailing lists hosted on SourceForge (pre-Discourse), at https://sourceforge.net/p/chapel/mailman/.

I think it would be good to download some kind of archive of these lists in case SourceForge decides to make them inaccessible in the future. According to https://sourceforge.net/p/forge/documentation/Mailing%20List%20Archives/ it should be possible for the administrator to download the archive as an mbox file -- so this is probably a task for @bradcray .

Since (AFAIK) all the contents of the archives are already available publicly, I suggest putting them in a git repo under the chapel-lang organization. No particular reason to use git other than that it's how we store all our other public artifacts.

[bradcray]

I've grabbed these files and have polled the team to make sure nobody objects to the proposal (not that I'm expecting that, just don't want to act without some consensus).