A follow-up to https://github.com/patternfly/react-component-groups/pull/366

What is necessary:

• enhance SectionGallery to support third level of navigation
• enhance SectionGallery to hide filters when appropriate flag is passed
• create galleries for every component category in "About component groups"

More context:
In the next phase, we have a gallery for each category and within the gallery, the cards are the individual component groups

We need to enhance the SectionGallery to support that

The code lives here:
https://github.com/patternfly/patternfly-org/blob/main/packages/documentation-framework/components/sectionGallery/sectionGallery.js

at the same time, it would be nice to add a prop hiding the filter if there is just a few components in the category

https://github.com/patternfly/react-component-groups/issues/369