Automatic merge from submit-queue (batch tested with PRs 46552, 46608, 46390, 46605, 46459)
Move admission lifecycle to genericapi
**What this PR does / why we need it**: ends the whole sequence of moving some admission plugins to generic api.
**Release note**:
```release-note
NONE
```
lifecycle plugin: make use of the libraries under k8s.io/client-go/pkg/api and k8s.io/client-go/kubernetes
for the client libraries instead of k8s.io/kubernetes/client/*
move registration to AdmissionOptions
Automatic merge from submit-queue (batch tested with PRs 45346, 45903, 45958, 46042, 45975)
ResourceQuota admission control injects registry
**What this PR does / why we need it**:
The `ResourceQuota` admission controller works with a registry that maps a GroupKind to an Evaluator. The registry used in the existing plug-in is not injectable, which makes usage of the ResourceQuota plug-in in other API server contexts difficult. This PR updates the code to support late injection of the registry via a plug-in initializer.
Automatic merge from submit-queue (batch tested with PRs 41931, 39821, 41841, 42197, 42195)
Apiserver: wait for Etcd to become available on startup
fixes#37704
Automatic merge from submit-queue (batch tested with PRs 40932, 41896, 41815, 41309, 41628)
enable DefaultTolerationSeconds admission controller by default
**What this PR does / why we need it**:
Continuation of PR #41414, enable DefaultTolerationSeconds admission controller by default.
**Which issue this PR fixes**:
fixes: #41860
related Issue: #1574, #25320
related PRs: #34825, #41133, #41414
**Special notes for your reviewer**:
**Release note**:
```release-note
enable DefaultTolerationSeconds admission controller by default
```
Automatic merge from submit-queue
Removed HPA objects from extensions api group
fix#29778
``` release-note
HorizontalPodAutoscaler is no longer supported in extensions/v1beta1 version. Use autoscaling/v1 instead.
```
cc @kubernetes/autoscaling