Goal

Add a note or instruction to BACKUP AND RESTORE BY USING VM SNAPSHOTS that before taking a snapshot, make sure to freeze guest using the QEMU guest agent. 

Feature description

When taking an online vm snapshot it is highly recommended to have qemu guest agent freezing the guest before taking the snapshot. This feature will add a screen tip for the users.

Users can take an online snapshot if the guest agent doesn't exist. The user needs to be made as aware as possible that this is not recommended, and explain how it can be fixed (installing qemu GA). To do that we want to add an alert that will be generated in cases when an on online snapshot occurred without a GA, the alert will refer to a run-book explaining how this should be fixed.  

Even if GA exists it is possible to have freeze error. When that occurs the snapshot can succeed or fail eventually. In either case we want to present that there was some failure during freeze and we can't fully guaranty that the snapshot is optimal. An indication will be presented on the snapshot indications. Once this indication is set we want to fire and alert explaining the situation and referring to a run-book explaining what can be done.

User stories

• As an OCP-virtualization user I would like to have better visualization of the vmsnapshot indications. `NoGuestAgent` indication and soon-to-be `QuiesceFailed` indication ( PR ) are important indication the should probably be addressed.
• As a writer, if new alerts are added to support this feature, then I might need to edit the descriptions in the runbooks to ensure that they are clear, concise, and understandable for our users. UPDATE: runbooks are being updated in CNV-69069. 
• As user, I want the documentation to contain guidance about the recommendations and limitations to ensure that I create the VM snapshots that I need.