manifest: remove pg_autoscaler from mgr modules examples

The pg_autoscaler mgr module is no longer possible to disable.
Ceph requires the module to always be enabled. Now the
autoscaling configuration is done with a per-pool setting.

Now the rook module is shown as an example to enable.

Signed-off-by: travisn <tnielsen@redhat.com>

Documentation/CRDs/Cluster/ceph-cluster-crd.md

@@ -61,7 +61,7 @@ For more details on the mons and when to choose a number other than `3`, see the
 	updates the label `mgr_role` on the mgr pods to be either `active` or `standby`. Therefore, services need just to add the label
     `mgr_role=active` to their selector to point to the active mgr. This applies to all services that rely on the ceph mgr such as
 	the dashboard or the prometheus metrics collector.
-    * `modules`: is the list of Ceph manager modules to enable
+    * `modules`: A list of Ceph manager modules to enable or disable. Note the "dashboard" and "monitoring" modules are already configured by other settings.
 * `crashCollector`: The settings for crash collector daemon(s).
     * `disable`: is set to `true`, the crash collector will not run on any node where a Ceph daemon runs
     * `daysToRetain`: specifies the number of days to keep crash entries in the Ceph cluster. By default the entries are kept indefinitely.

deploy/examples/cluster.yaml

@@ -57,10 +57,10 @@ spec:
     count: 2
     allowMultiplePerNode: false
     modules:
-      # Several modules should not need to be included in this list. The "dashboard" and "monitoring" modules
-      # are already enabled by other settings in the cluster CR.
-      - name: pg_autoscaler
-        enabled: true
+      # List of modules to optionally enable or disable.
+      # Note the "dashboard" and "monitoring" modules are already configured by other settings in the cluster CR.
+      # - name: rook
+      #   enabled: true
   # enable the ceph dashboard for viewing cluster status
   dashboard:
     enabled: true