Add resource_kubernetes_env (#1838)

* initial resource commit

* add basic CRUD functions

* add metadata block and create logic

* add update function

* add force attribute

* add read function & getEnvs function

* add field_manager attribute

* fix read function

* Add read function

* Add Delete function

* draft createEnv function in test

* complete draft kubernetes_env_test.go

* remove unnecessary getEnvs function

* Finish Test for kubernetes_env_test

* Add kubernetes_env docs

* add value_from attribute to tests

* add value_from to schema

* Add Flatten Function

* Update kubernetenv_test

* Add changelog-entry

* Format Env Docs

* Fix test format

* Update website/docs/r/env.html.markdown

Co-authored-by: John Houston <jrhouston@users.noreply.github.com>

* Last Formatting Steps

* Update structures_container.go

* Add changelog-entry

* Delete extra changelog

* Add missing info

* Add changelog-entry

* Description Change

Co-authored-by: John Houston <jrhouston@users.noreply.github.com>

.changelog/1838.txt

@@ -0,0 +1,3 @@
+```release-note:new-resource
+Add resource_kubernetes_env.go
+```

kubernetes/provider.go

@@ -253,6 +253,7 @@ func Provider() *schema.Provider {
 			"kubernetes_pod_v1":                     resourceKubernetesPod(),
 			"kubernetes_endpoints":                  resourceKubernetesEndpoints(),
 			"kubernetes_endpoints_v1":               resourceKubernetesEndpoints(),
+			"kubernetes_env":                        resourceKubernetesEnv(),
 			"kubernetes_limit_range":                resourceKubernetesLimitRange(),
 			"kubernetes_limit_range_v1":             resourceKubernetesLimitRange(),
 			"kubernetes_persistent_volume":          resourceKubernetesPersistentVolume(),