stakeholders group is not an openid mapping to a LP group

Last night David requested to see the reporting dashboard for myapps, so I checked the code and configs and couldn't see a Launchpad group openid mapping for the stakeholders Django group.

So currently people have to be added in the django admin interface to give them access (or given the correct permission in the admin interface), where as we should instead have a Launchpad group from which people can be updated (consistent with the other privileges).

For ref, here is the irc conversation: https://pastebin.canonical.com/55571/

Note: The arb-reviewers django group is also not linked to a launchpad group.