feat(app): use PV to hibernate/resume sessions

[m-alisafaee]

Adds a /notebooks/servers/<server_name> endpoint with PATCH method that accepts a state argument. Setting state to hibernated makes the server to go to hibernation and setting state to running resumes a hibernated server.

When hibernating a server:

• spec.jupyterServer.hibernated is set to True in the server's manifest file.
• Server's sidecar is queried (via JSON RPC) and some info about the repository (commit, branch, dirty, synched) along with hibernation date are added to server's annotations.
• If querying the sidecar fails, all those annotation except hibernation date will be empty.
• By seeing spec.jupyterServer.hibernated set to true, Amalthea scales server's statefulset to have 0 replicas and set's server's state to hibernated.

When resuming:

• spec.jupyterServer.hibernated is set to False in the server's manifest file.
• All server's hibernation annotations are cleared (including the date)
• By seeing spec.jupyterServer.hibernated set to false, Amalthea scales server's statefulset to have 1 replica.

It also adds a renku.io/hibernatedSecondsThreshold annotation to the server that shows when a hibernated sessions will be deleted.

Related: SwissDataScienceCenter/amalthea#344

/deploy #persist extra-values=notebooks.userSessionPersistentVolumes.enabled=true,notebooks.amalthea.image.repository=renku/amalthea,notebooks.amalthea.image.tag=db70f80ef1983d49a1b167faa57d02d9d8b9554f renku-ui=leafty/2526-feature-persistent-sessions

[RenkuBot]

You can access the deployment of this PR at https://renku-ci-nb-1518.dev.renku.ch