doc/mgr: add progress module documentation

This PR ingests the work added to the documentation
in PR#29335.

The technical information in this PR concerns the
installation and use of the "Progress Module".

Signed-off-by: Zac Dover <zac.dover@gmail.com>
Signed-off-by: kamoltat <ksirivad@redhat.com>

doc/mgr/index.rst

@@ -47,3 +47,4 @@ sensible.
     Rook module <rook>
     MDS Autoscaler module <mds_autoscaler>
     NFS module <nfs>
+    Progress Module <progress>

doc/mgr/progress.rst

@@ -0,0 +1,47 @@
+Progress Module
+===============
+
+The progress module is used to inform users about the recovery progress of PGs
+(Placement Groups) that are affected by events such as (1) OSDs being marked
+in or out and (2) ``pg_autoscaler`` trying to match the target PG number.
+
+The ``ceph -s`` command returns something called " Global Recovery Progress",
+which reports the overall recovery progress of PGs and is based on the number
+of PGs that are in the ``active+clean`` state.
+
+Enabling
+--------
+
+The *progress* module is enabled by default, but it can be enabled manually by
+running the following command:
+
+.. prompt:: bash #
+
+  ceph progress on
+
+The module can be disabled at anytime by running the following command:
+
+.. prompt:: bash #
+
+  ceph progress off
+
+Commands
+--------
+
+Show the summary of all the ongoing and completed events and their duration:
+
+.. prompt:: bash #
+
+  ceph progress
+
+Show the summary of ongoing and completed events in JSON format:
+
+.. prompt:: bash #
+
+  ceph progress json
+
+Clear all ongoing and completed events:
+
+.. prompt:: bash #
+
+  ceph progress clear