Add option to display breadcrumbs below post content

[cjg89]

Description

Add an option to display a basic Athena breadcrumb bar underneath the page content (above the site footer).

We've implemented this already in the FinAid Child Theme as a feature dependent on Yoast SEO, but we'll want to add more granular control over how breadcrumbs are activated, and ensure compatibility with our other CPT/taxonomy plugins (FAQs comes to mind, since it requires special overrides).

Why it's Important

• We've started using breadcrumbs on a handful of sites, and it'd be nice to incorporate it here vs in child themes.
• Breadcrumbs offer extra context and navigation for users.

Alternatives

Possible Implementation

Example from Coronavirus Child Theme: https://github.com/UCF/Coronavirus-Child-Theme/pull/17/files

Additional context