Make the Applications Panel admin UI simpler to discover and use

Problem:
Some applications are not discoverable by a new Admin on XWiki because they are not displayed in the Application Panel.
I'll take the Invitation App example which is useful for Admin when they need to invite users: 

• As the Admin doesn't see this app in the Application Panel, he thinks it is not installed and searches on Google and lands here http://extensions.xwiki.org/xwiki/bin/view/Extension/Invitation%20Application.
• Then he tries to install it and cannot find it in the Extension Manager.
• So he starts wondering where it is.
• He might land at Application Index, sees it but cannot figure out how to start it.

The only way is that he gets to land to the "Manage application Panel" page which is not really discoverable (+1 explanation is that there is no link to it from "Application Index Page").

Ideas :
1/ Display a "Manage Application Panel" link under "More Apps" (visible only by Admins)
2/ Display the same link with the "Application Index"

+ following relevant Anca's observation, that hint the Admin to remove the App from the "Application Panel" after use if it is not necessary that non-admin users see it.