<rh-filter> Need a new filter component

[markcaron]

Primarily used for search filtering, but could be used in other situations where filtering results is needed.

This will likely require a bit of discussion around what this filter should look like, especially considering the different needs across our site systems.

Example usage on redhat.com

Another example on access.redhat.com

And, I'm sure there's more out in the wild.

Things to consider in development:

• What format does the data come in from Solr, JSON?
• What does the schema look like for the returned data?

Related links:

XD mockups for RHDC: https://xd.adobe.com/view/d20a1c17-375c-4c7f-6827-5fe2f8c2d92f-a43b/screen/e58e8471-6ae6-43e2-8cce-97c287c6e25f/
Original PFE issue: patternfly/patternfly-elements#940