Adapt package controller specs

Change one redirection from package_edit to package_show to follow
changes from the webui2 version of the package controller.

Remove package#binaries specs and cassettes. Those are feature specs
which we will need to cover, they aren't right now.

Fix the package#statistics specs, but they should be feature specs.

Co-authored-by: Victor Pereira <vpereira@suse.com>