* Component: vf-bookmark

Creates an initial vf-bookmark with a few options:

- label_inactive: Add as bookmark
- label_active: Bookmarked
- is_active: false
- modifier: button or inline
- icon: heart or star

for #1654

* Add bookmark_href

* Adds css, docs

* Show sample active/inactive states

* add aria-hidden="true"

* Update README.md