Remove unused permissions

There's unused permissions on orders and partners that interfere with
our permission-based dashboard.
Introduce permission checking logic and decorator

Allows passing a list or two-tuple of lists of permissions that are
checked against the user.
Add support for permission checking to core Application class

Allows specifying default permissions and individual permissions based
on view names.
Move dashboard apps to new permission handling

Effective permissions are unchanged apart from catalogue views, which now
also allow users that have both partner.dashboard_access and
catalogue.change_product as permissions.

Includes tests.
Filter dashboard menu based on users's permissions

Introduces a default filter function that only returns dashboard menu
nodes that the user can access.
Handle permissions for ProductDeleteView

Required updating tests.
Handle permissions for ProductListView

Added tests as well.
Handle product permissions for ProductCreateUpdateView