Create a place to gather information about the different mailing lists, and their scope and policy

lists: -project, -news, -ux, -dev, -testers, -l10n, -press, -fundraising, -sysadmins, -security.

If I forgot any, add it to the list :)

When this ticket is closed, #7937 (closed) can be closed too, as it’s done here.

Feature Branch: web/7698-contacts

Original created by @sajolida on 7698 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information