Add UI Navigation for Analytics by Application to /admin/stats

When setting a user's permissions to Analytics only there is no way to navigate to each application's analytics.

The page for each application analytics is still accessible via URL:

https://<subdomain>-admin.3scale.net/buyers/stats/applications/<application_id>

But there is no navigation to this URL. So perhaps a section similar to "Top Applications" that has a list of all applications that then links to the corresponding stats page.

This is important for setting up users that ONLY have read only access to analytics, but still need to be able to monitor analytics on a per application basis. They have no way to navigate to the application analytics page at all.