implement gardenctl wakeup to wake up a shoot cluster and gardenctl hibernate to hibernate a shoot cluster after shoot targeted

[neo-liang-sap]

as titled.
After shoot is targeted,

If the shoot is hibernated, gardenctl wakeup will wakeup the shoot, wait until shoot waked up.
If the shoot is not hibernated, print out msg indicating the shoot status.

If the shoot is not hibernated, gardenctl hibernate will hibernate the shoot, wait until shoot hibernated.
If the shoot is hibernated, print out msg indicating the shoot status.
/assign

[anoopjb]

IMHO, This gardenctl feature will be useful. 👍

In our Jenkins CI runs we need to wake the cluster when the build starts and hibernate when the job finishes.
Now we are planning to use kubectl patch shoot to set /spec/hibernation/enabled and achieve hibernation. We feel this approach will break at some point when there is a change in the shoot CRD.
It will be nice to have this support from gardenctl.

[neo-liang-sap]

i will work on this issue when available
/reopen