Formalize the release process

[zachsmith1]

We should ideally be creating releases for groups of work that has landed and is ready to promote. To start, we should try and follow what https://github.com/datum-cloud/milo has been doing

[mustela]

@zachsmith1 we used to have a process https://github.com/datum-cloud/cloud-portal/releases, we even had autogenerated changelogs datum-cloud/cloud-portal#344, but that was gone, and moved into milo somehow. When releasing milo, the portals are also being released.
So I guess when that's happens, a release should be created in the staff/cloud portals too. Is that what you mean?