add breadcrumps

[Muescha]

Describe the feature you'd like:

when i am in a deep subcategory i can go only back with the "hamburger menu" to the topmost category

Suggested implementation:

add a breadcrump element or a link to the next higher category, that the user can navigate better.

Describe alternatives you've considered:

Teachability, Documentation, Adoption, Migration Strategy:

[Panpi]

Hi @muescha
This is a good one!
Think it is enough to have a straightforward implementation using gatsbystorefront-config.js and it's menu object as data source to create breadcrumbs.

[zach]

This starter is awesome!