Load plugin configuration field value from Kubernetes Secret

Co-authored-by: nnlquan <longquan0104@gmail.com>

pkg/provider/kubernetes/crd/fixtures/with_plugin_deep_read_secret.yml

@@ -0,0 +1,24 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: name
+  namespace: default
+
+data:
+  key: dGhpc19pc190aGVfdmVyeV9kZWVwX3NlY3JldA==
+
+---
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: test-secret
+  namespace: default
+
+spec:
+  plugin:
+    test-secret:
+      secret_0:
+        secret_1:
+          secret_2:
+            user: admin
+            secret: urn:k8s:secret:name:key

pkg/provider/kubernetes/crd/fixtures/with_plugin_read_array_of_map_contain_secret.yml

@@ -0,0 +1,25 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: name
+  namespace: default
+
+data:
+  key1: YWRtaW5fcGFzc3dvcmQ=
+  key2: dXNlcl9wYXNzd29yZA==
+
+---
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: test-secret
+  namespace: default
+
+spec:
+  plugin:
+    test-secret:
+      users:
+        - name: admin
+          secret: urn:k8s:secret:name:key1
+        - name: user
+          secret: urn:k8s:secret:name:key2

pkg/provider/kubernetes/crd/fixtures/with_plugin_read_array_of_secret.yml

@@ -0,0 +1,23 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: name
+  namespace: default
+
+data:
+  key1: c2VjcmV0X2RhdGEx
+  key2: c2VjcmV0X2RhdGEy
+
+---
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: test-secret
+  namespace: default
+
+spec:
+  plugin:
+    test-secret:
+      secret:
+        - urn:k8s:secret:name:key1
+        - urn:k8s:secret:name:key2

pkg/provider/kubernetes/crd/fixtures/with_plugin_read_not_exist_secret.yml

@@ -0,0 +1,11 @@
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: test-secret
+  namespace: default
+
+spec:
+  plugin:
+    test-secret:
+      user: admin
+      secret: urn:k8s:secret:notfound:key

pkg/provider/kubernetes/crd/fixtures/with_plugin_read_secret.yml

@@ -0,0 +1,21 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: name
+  namespace: default
+
+data:
+  key: dGhpc19pc190aGVfc2VjcmV0
+
+---
+apiVersion: traefik.containo.us/v1alpha1
+kind: Middleware
+metadata:
+  name: test-secret
+  namespace: default
+
+spec:
+  plugin:
+    test-secret:
+      user: admin
+      secret: urn:k8s:secret:name:key