Changes to GET /api/appointments

added the new optional query request parameter exclude_membership

added subschema #1: AvailabilityDateRangeResponse subschema #2: AvailabilitySingleDateResponse to the response body oneOf list for the response status 200

the response's body type changed from object to no type for status 200

removed the optional property data from the response with the 200 status

removed the optional property next from the response with the 200 status

removed the optional property previous from the response with the 200 status