Feat: takeover & readonly policy (#5102)

* Feat: takeover & readonly

Signed-off-by: Somefive <yd219913@alibaba-inc.com>

* Feat: add tests

Signed-off-by: Somefive <yd219913@alibaba-inc.com>

* Feat: add cue def for read-only and take-over

Signed-off-by: Somefive <yd219913@alibaba-inc.com>

* Docs: add example doc

Signed-off-by: Somefive <yd219913@alibaba-inc.com>

Signed-off-by: Somefive <yd219913@alibaba-inc.com>

references/docgen/def-doc/policy/read-only.eg.md

@@ -0,0 +1,22 @@
+```yaml
+apiVersion: core.oam.dev/v1beta1
+kind: Application
+metadata:
+  name: read-only
+spec:
+  components:
+    - name: busybox
+      type: worker
+      properties:
+        image: busybox
+        cmd:
+          - sleep
+          - '1000000'
+  policies:
+    - type: read-only
+      name: read-only
+      properties:
+        rules:
+          - selector:
+              resourceTypes: ["Deployment"]
+```

references/docgen/def-doc/policy/take-over.eg.md

@@ -0,0 +1,23 @@
+```yaml
+apiVersion: core.oam.dev/v1beta1
+kind: Application
+metadata:
+  name: take-over
+spec:
+  components:
+    - name: busybox
+      type: k8s-objects
+      properties:
+        objects:
+          - apiVersion: apps/v1
+            kind: Deployment
+            metadata:
+              name: busybox-ref
+  policies:
+    - type: take-over
+      name: take-over
+      properties:
+        rules:
+          - selector:
+              resourceTypes: ["Deployment"]
+```