Doc: Export application improvements

Background 

• Export application will be available from the + Add view in the developer perspective. This feature already exists in the Topology view after you install the gitops-primer-system operator, but I'm not sure if this feature in the Topology view only existed for a developer preview from reading what's new blogs from PM (Serena Nicols). I cannot find any reference to the export application feature in the topoloy view in the 4.11 doc.  I will add a comment to the epic asking if the export application feature in both the +Add view and for the Topology view is a tech preview/GA feature for 4.12.
• 4.12 Miro board highlighting export application feature

• 4.9 what's new blog describing export application feature
• 4.10 what's new blog describing feature enhancement
• Engineering PR with video of feature completed

Scope of work

It seems like a small blurb would be needed to two topics, assuming feature is going out tech preview/GA levels for 4.12:

• Small blurb highlighting feature: https://docs.openshift.com/container-platform/4.11/applications/odc-viewing-application-composition-using-topology-view.html
• Small blurb highlighting feature: https://docs.openshift.com/container-platform/4.11/applications/creating_applications/odc-creating-applications-using-developer-perspective.html
• Review the engineering epic further to see if other update are needed.