Add button, which allows to assign several packages to one category at a time

In Kilo release, we are adding category management support.
Admin user can add new category, but could apply it only for one package at a time.

Need to add new button, called "Manage categories", to the 'Package Definition' page. It will be active, only if packages are selected and should do the following:

* Open list with all categories, where categories that belongs to packages will be highlighted
* User should be able to select/unselect any category one by one;
* Selectors should have three states of category assignment:
    a) All
    b) Some
    c) None
* After all changes are made, selected packages should be updated with categories, that user just picked.