Display total number of packages in all three main views

[drws]

Is your feature request related to a problem? Please describe.

There is a very basic piece of information missing in main tabs/views (Explore, Installed and Updates) - the total count of packages in the current view. For example there is no way to see the number of installed apps.

Describe the solution you'd like

For all three main views to provide the total package count. In the Explore tab meaning the number of packages given the current search filters.