ApplicationStatus #updated and #ready?

The following discussion from !23924 (merged) should be addressed:

• @ayufan started a discussion:

  For future, I would even say that this should be part of app_status concern, with the method ready?. It seems useful for others.

• Also we should aim to get rid of updated in favor of installed, see https://gitlab.com/gitlab-org/gitlab-ce/issues/56524#note_132674575 and discussion ensuing