As an editor/maintainer I want to specify categories for Bundle to make them filterable on the frontend

Creating a category

Bundle category is a Tag under tag `Bundle Categories`.

Specifying a category

There is a new field for `Bundle` content type: bundle_category

Frontend

It should be possible to select particular tag in the Categories menu (see mockup);
Template for Category should be the same as for the Bundle list;
Tags in the menu should be ordered the same way as Tags in the admin ui.