Surface control plane notification in the drawer

Goal
Surface a notification in the drawer for when worker nodes are paused (when a user selects a control plane upgrade only in the console).

Background
This is an extension to adding the ability to update the control plane only in the UI.

Requirements

1. Add a new notification to the drawer to notify users to complete the rest of the update.
2. In the alert, include the sentiment that:
   1. there is a 60 day window to update all worker pools
   2. worker pools can remain paused as long as is normally safe, which means until certificate rotation becomes critical which is at about 60 days. The admin would be advised to unpause them in order to complete the full upgrade. If the MCPs are paused, the certification rotation does not happen, which causes the cluster to become degraded and causes failure in multiple 'oc' commands, including but not limited to 'oc debug', 'oc logs', 'oc exec' and 'oc attach'. (Are we missing anything else here?)
3. If possible, follow a similar logic to the alerts on the cluster settings and machine config pool page:
   1. From day 60 to day 10 (would it be best to add this as a recommendation notification like we do with updates today?)
   2. From day 10 to day 3 use the warning alert.
   3. From day 3 to 0 use the critical alert and continue to persist until resolved.

Questions:

1. Do we need to involve update team or other teams to provide alerts via API?
   • Note [in speaking with Trevor]: hopefully something involved in the certificate rotation process would have alerts set up to fire on unrotated CAs, and then with escalated severity as we got closer to expiration time. If we decide to alert just on pool, that seems like  [info]level. The cert-rotation aspect deserves alerts that don't care about pool behavior (e.g. maybe the pool is unpaused, but hung on a slow-to-drain node; you'd still want "you have stale certs that expire tomorrow" up in your face).

Design deliverables: 

• Doc
• Marvel