Merge pull request #50998 from zjj2wry/set-env

Automatic merge from submit-queue (batch tested with PRs 51377, 46580, 50998, 51466, 49749)

feat(#21648 )Add kubectl set env command.

**What this PR does / why we need it**:
#21648
Moved from OpenShift to Kubenetes.
@kargakis @smarterclayton 

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

hack/testdata/configmap.yaml

@@ -0,0 +1,7 @@
+apiVersion: v1
+data:
+  key-1: value-1
+  key-2: value-2
+kind: ConfigMap
+metadata:
+  name: test-set-env-config

hack/testdata/secret.yaml

@@ -0,0 +1,8 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: test-set-env-secret
+type: Opaque
+data:
+  password: dmFsdWUtMg0K
+  username: dmFsdWUtMQ0K