DOCS-518 add replSetMaintenance

Author: kay-kim

source/reference/command/replSetMaintenance.txt

@@ -0,0 +1,25 @@
+==================
+replSetMaintenance
+==================
+
+.. default-domain:: mongodb
+
+.. dbcommand:: replSetMaintenance
+
+   The :dbcommand:`replSetMaintenance` command enables/disables the maintenance
+   mode.
+   
+   The command has the following prototype format:
+
+   .. code-block:: javascript
+
+      { replSetMaintenance: <boolean> }
+
+   Consider the following behavior when running the
+   :dbcommand:`replSetMaintenance` command:
+   
+   - You cannot run the command on the Primary.
+   - You must run the command against the ``admin`` database.
+   - When enabled ``replSetMaintenance: 1``, the member will change state to ``RECOVERING``.
+
+   .. admin-only

source/reference/commands.txt

@@ -387,6 +387,9 @@ Internal Use
 .. include:: command/replSetFresh.txt
    :start-after: mongodb
 
+.. include:: command/replSetMaintenance.txt
+   :start-after: mongodb
+
 .. include:: command/replSetTest.txt
    :start-after: mongodb