Add the Ability to Style and Add Text to Booked Timeslots

[korymcandrew]

From what we can tell the booked timeslots are represented by the absence of HTML rather than an HTML slot that is styled to disappear and/or display nothing. It would be nice to have the ability to style booked timeslots via CSS and it would also be nice to add localized text to a booked slot (e.g. "Not Available").

[laander]

@korymcandrew That's not a bad idea. It however quite difficult to accomplish right now because the POST /findtime endpoint that provides availability, only return timeslots that are not booked yet/available. Using GET /bookings, you can however retrieve existing bookings, so with a hack it could probably be implemented.