Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Critical pod priorityClass addition
**What this PR does / why we need it**:
@bsalamat - Apologies for the delay. This PR is to ensure that all pods with priorityClassName `system-node-critical` and `system-cluster-critical` will be critical pods while preserving backwards compatibility.
**Special notes for your reviewer**:
- Moved some constants and other data structures to scheduler/api/types.go where other constants are present.
- An automatic assignment of critical priorities to pods based on critical pod annotation for backwards compatibility including some unit tests.
xref: https://github.com/kubernetes/kubernetes/issues/57471
**Release note**:
```release-note
Critical pods to use priorityClasses.
```
This is part of the "Debug Containers" feature and is hidden behind
a feature gate. Debug containers have no stored spec, so this new
runtime label allows the kubelet to treat containers differently
without relying on spec.
Automatic merge from submit-queue (batch tested with PRs 47694, 47772, 47783, 47803, 47673)
Make different container runtimes constant
Make different container runtimes constant to avoid hardcode
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue
Generates DELETE pod update operations
fixes#27105
Generates DELETE pod update operations to make the code and log more intuitive.
1. main refactoring is in `kubelet/config`
2. kubelet will log if it received DELETE, just like other OPs
cc @Random-Liu :)
Add `kube-reserved` and `system-reserved` flags for configuration
reserved resources for usage outside of kubernetes pods. Allocatable is
provided by the Kubelet according to the formula:
```
Allocatable = Capacity - KubeReserved - SystemReserved
```
Also provides a method for estimating a reasonable default for
`KubeReserved`, but the current implementation probably is low and needs
more tuning.