Support page header (page hero) in archive-taxonomy layouts (#2320)

* Support page header in archive-taxonomy layout

Merge branch 'release/4.0.4'

Conflicts:
	README.md

Merge branch 'feature/theme-gem' into develop

Replace base_path with `absolute_url` filter where possible

Merge branch 'release/3.0.0'

Merge branch 'feature/documentation-and-demo' into develop

Fix path bugs in breadcrumbs

Merge branch 'feature/visual-refresh' into develop

DRY up archive include
- Combine grid and list view into one include

More style cleanup and housekeeping

Add support for Jekyll Archives plugin
- Option to select GitHub Pages compatible tag/category page archive or plugin generated archives