WTD: Projected volumes (#3856)

* Update projected volume task

- Rename file
- Build out steps
- Create separate yaml file for pod configuration
- Add new page to the sidenav

* Add projected volume type to volumes concept page

docs/tasks/configure-pod-container/projected-volume.yaml

@@ -0,0 +1,23 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: test-projected-volume
+spec:
+  containers:
+  - name: test-projected-volume
+    image: busybox
+    args:
+    - sleep
+    - "86400"
+    volumeMounts:
+    - name: all-in-one
+      mountPath: "/projected-volume"
+      readOnly: true
+  volumes:
+  - name: all-in-one
+    projected:
+      sources:
+      - secret:
+          name: user
+      - secret:
+          name: pass