If a resource class is edited significantly the session may not resume

[olevski]

To replicate:

• start a session using a resource class with a quota
• hibernate the session
• go to the admin panel and remove the quota
• resume the session (it will not start)

This is because when we resume we do not check for the priority class assignment that comes from the quota.

In broader terms also I am not sure if we check whether the resource class that the session was started with still exists or not. And if the resource class does not exist then we should allow users to edit it / choose a different one.

[olevski]

This is potentially a 2 part fix/feature mix:

• fix for changes to the priority class when resuming
• feature / fix for gracefully handling missing resource classes when resuming

[olevski]

Found on renku version 0.61.2