Add category highlight and breadcrumbs when necessary

## From a reader's perspective

For now when browsing any of the three categories “Documentation”, “Product updates” or “Guides”, as a reader I don't know in which of these categories I am.

## My thoughts on how to solve

In the Documentation, we have a sidebar which helps to navigate and understand we are in the same “space”. So it's kind of ok.

But in both the “product updates” and “Guides” category, the reader doesn't really know where he is. In my opinion that's because of two reasons:
- We could highlight the category in the top nav bar

I'm thinking of something like:
- We could have a breadcrumb below the top nav bar:
- in case of the “product updates” it could be a date/time slider for example
- in case of the “Guides” it could be the main categories (which we already have in the home page of guides, but loose when reading an article)