Type Alias OpeningHoursSpecification

MVF uses a more permissive version of this spec: (http://schema.org/OpeningHoursSpecification) The key difference is that MVF (like Google: https://developers.google.com/search/docs/data-types/local-businesses) accepts dayOfWeek as an array as well as an individual day. In addition, we accept day of week as a string rather than a canonicalized string.

Behavioral notes:

• if the "opens" property is not present, the location is closed, and the closes property is ignored (Schema.org style)
• if opens/closes are both set to 00:00, the location is closed (Google style)
• If special hours do not specify certain weekdays being open, those weekdays are closed.
• Not specifying dayOfWeek is equivalent to specifying every day of the week.
• The '@type' property is optional