Get a list of available booking start times for a particular day.
The available durations and prices are included under each start time.
If person_id and resource_id are not specified and the service has multiple people or
resources (as specified by the who/what/where config), times that are the same but differ by
person or resource are merged together by default. If booking a particular person or
resource either pass in their IDs in the person_id and resource_id params or pass the
merge_times param as false.
Requested Assets (requested_assets), this parameters describe a list of rules which a time must
satisfy to be considered available.
A Requested asset consists of a

• company_rule -> can be either default (it will respect the company of the URL), any (it can be any company that provides the service), or Array<CompanyID> one of these companies (which must provide the service).
• person_rule -> can be either any (any person which provides the service), any_or_none (the user is indifferent as to whether a person is associated to the booking), Array<PersonID> one of these people who provide the service.
• resource_rule -> same as person_rule: can be either any (any resource which provides the service), any_or_none (the user is indifferent as to whether a resource is associated to the booking), Array<PersonID> one of these resources with which the service can be provided.
  Factors that influence availability include:
• Service, Person and Resource schedules
• Bookings and blocked time
• Company opening hours
• Max/min advance
• Min/max consecutive bookings (fixed time service)
• Durations (flex time service)
• Travel time (flex time service)
• Booking time step