Filter to show only the licenses used within my portfolio

Another filtering enhancement idea/suggestion related to #146 but a little more involved.

Under the Licenses section, it would be useful to be able to filter/toggle showing only the licenses used in your portfolio. Though I'm not sure if the tool currently links components to a license so this would be more involved than just filtering.

No files, tests, or entry points are named. Start by determining whether portfolio components are linked to licenses, then trace the existing Licenses section and filtering behavior; done means a portfolio can be toggled to show only licenses used by its components.

Written by the indexing model from the issue text.