Removal of availability check endpoint in favour of OrderQuote #98
Description
Since SessionSeries and ScheduledSession, and FacilityUse and Slot are often found in different RPDE feeds and due to Offer inheritance, constructing an object that will be useful for returning the availability of a number of slots is non-trivial.
Furthermore when there are a large number of available Slots (e.g. for squash court) or ScheduledSessions (e.g Virtual RPM classes which run very frequently), the response to "get all Slots within the FacilityUse" or "get all ScheduledSessions within a SessionSeries" can be large and will likely need to be filtered further. Given this complexity, getting just the availability for a single Slot or ScheduledSession would be preferable, however due to Offer inheritance this can also be of limited use, and quickly converges with the functionality already available from OrderQuote.
More detail of these issues can be found here: #91
As a result of the above complexity, this specification no longer includes the Opportunity API to retrieve aspects of the opportunity data, and relies on using RPDE feeds only to get the Customer to the point of selecting an item to begin the booking journey with.
Please comment here with specific use cases that would justify re-inclusion of the Opportunity API aspects here.