Add breadcrumbs to taxonomy result list

[at055612]

Fixes #1004

• Adds a card around each item in the taxonomy result list
• Adds a breadcrumb line to each taxonomy result
  • Makes it clear the location of the item
  • Provides the means to open an ancestor of a result item
  • Can be disabled using site param taxonomy_breadcrumb_disable, enabled by default
• Changed the breadcrumb so that the leaf item is not a clickable link

I think the cards could do with some drop shadow but I haven't added it as I wasn't sure it was consistent with the rest of the theme.

Making the leaf item not a link is possibly contentious but a quick google suggests this is an accepted practice. I think having a link to the page you are on is confusing and offers no value.

This is how it now looks on the example site

This is how it looks for a result that is at the root level.

But if .td-breadcrumbs__single { display: none !important; } is set in the project scss then you will see:

The page breadcrumbs now look like this:

[LisaFC]

This is great! @narrenfrei if you're free do you want to take a closer look at this as you did a lot of the taxonomy support? I'll take a look as well.

[raum51]

Looks fine - thank you for the great work!

[LisaFC]

Looks good to me! Thanks again.

[LisaFC]

Follow-up: can you add a quick update to the docs telling users how to disable the taxonomy breadcrumb feature if required?

[at055612]

Follow-up: can you add a quick update to the docs telling users how to disable the taxonomy breadcrumb feature if required?

@LisaFC Thanks for merging. See #1048 for the docs update.

[chalin]

@at055612 - why did you remove aria-current?

[at055612]

Good question. I can't remember why I took that out. Maybe because I don't think it is applicable when the breadcrumb is shown on the taxonomy list, however I agree it ought to be there for the page breadcrumbs. Will take a look.

[chalin]

For now I've reverted this change -- see #1068. We would need a bit more logic to remove (all?) the ARIA related labels for the taxonomy-list usage ... or maybe just use a regex to strip all aria labels from breadcrumbs in taxonomy list. I'll let you follow up on that if you think that it's worth it.