RHIDP-6675: Added screenshots to Extensions chapter (redhat-developer#1029)

* Added screenshots

* incorporated review comments

* review comments incorporated

Author: hmanwani-rh

images/rhdh-plugins-reference/dynatrace-certified-and-verified.png

@@ -3,6 +3,8 @@
 == Search by plugin name
 You can use the search bar in the header to filter the Extensions plugin cards by name. For example, if you type “A” into the search bar, Extensions shows only the plugins that contain the letter “A” in the Name field.
 
+image::rhdh-plugins-reference/dynatrace-certified-and-verified.png[Extensions catalog with a Dynatrace search]
+
 Optionally, you can use the search bar in conjunction with a filter to filter only plugins of the selected filter by name. For example, you can apply the *Category* filter and then type a character into the search bar to view only Openshift plugins that contain the typed character in the name.
 
 The following filters are available:

images/rhdh-plugins-reference/extensions-catalog-sidebar.png

@@ -6,4 +6,6 @@ You can view plugins available for your {product} application on the *Extensions
 .Procedure
 
 . Open your {product-short} application and click *Administration* > *Extensions*.
-. Go to the *Catalog* tab to view a list of installed plugins and related information.
+. Go to the *Catalog* tab to view a list of available plugins and related information.
++
+image::rhdh-plugins-reference/extensions-catalog.png[Extensions Catalog]

images/rhdh-plugins-reference/extensions-catalog.png

@@ -26,4 +26,8 @@ Highlights:: A list of plugin features.
 Install button:: Button to install the plugin (disabled).
 Long description:: Full description of the plugin (Markdown).
 Links:: Clickable links providing additional information about the plugin.
-Versions:: Displays the plugin's name, version, role, supported version, and installation status based on the plugin's plugin's package name. 
+Versions:: Displays the plugin's name, version, role, supported version, and installation status based on the plugin's package name.
+
+For example:
+
+image::rhdh-plugins-reference/extensions-catalog-sidebar.png[Extensions Catalog sidebar]