Restore Breadcrumbs and Fix breadcrumbs on special pages

[fthobe]

Currently breadcrumbs are not rendered correctly in some occasions:

• No breadcrumbs when clicking on a homepage product #130 Product pages (as defined in solidus issue #6047 do not render correctly as multiple taxons can be used for the generation of the breadcrumbs, therefor the decision was taken to create a breadcrumb selector defining one taxon as primary breadcrumb source for a product.
• System pages such Login produce wrong breadcrumbs #390 Special pages like Login / Cart / ... lack a breadcrumb definition as breadcrumbs_component.rb defaults to home > product if nothing is defined.

Solidus Version:
All Versions of starter frontend / solidus

To Reproduce
See detailed Issues linked above

Current behavior
See detailed Issues linked above

Expected behavior
Breadcrumbs render consistently across the entire template.

Screenshots
See detailed Issues linked above

Desktop (please complete the following information):
N/A

Smartphone (please complete the following information):
N/A