Implements the "video" apostrophe schema field type.
The value of the field is an object with
thumbnail properties, the latter
two being as obtained by
oembetter at the time the URL was originally pasted and fetched
This field type is locked down to accept only URLs whose oembed response type
Videos are not actually hosted or stored by Apostrophe. They are displayed via oembed-capable third party services like Vimeo and YouTube.