[QoS Booking And Assignment] Review and remove invalid error response codes #129

Problem description
The API defines some error response codes that do not appear applicable to the API.

For example:

Booking:
400 OUT_OF_RANGE (GET/DELETE /qos-bookings/{bookingId})
403 INVALID_TOKEN_CONTEXT (All endpoints)
404 IDENTIFIER_NOT_FOUND (GET/DELETE /qos-bookings/{bookingId})
409 ABORTED, ALREADY_EXISTS, CONFLICT, INCOMPATIBLE_STATE (Defined for POST /qos-bookings and DELETE /qos-bookings/{bookingId} - are these all required? How are they used?)
422 MISSING_IDENTIFIER, UNSUPPORTED_IDENTIFIER, UNNECESSARY_IDENTIFIER (Defined for POST /qos-bookings - which does not accept and explicit device identifier)

Assignment:
400 OUT_OF_RANGE (GET /qos-bookings/{bookingId}/devices)
400 QOS_BOOKING_AND_ASSIGNMENT.DURATION_OUT_OF_RANGE (POST /qos-bookings/{bookingId}/devices/assign)
403 INVALID_TOKEN_CONTEXT (all endpoints)
404 NOT_FOUND (POST /qos-bookings/retrieve)
404 IDENTIFIER_NOT_FOUND (GET /qos-bookings/{bookingId}/devices)
409 ABORTED, ALREADY_EXISTS, CONFLICT, INCOMPATIBLE_STATE (POST /qos-bookings/{bookingId}/devices/assign - are these all required? How are they used?)
422 SERVICE_NOT_APPLICABLE, MISSING_IDENTIFIER, UNSUPPORTED_IDENTIFIER, UNNECESSARY_IDENTIFIER (GET /qos-bookings/{bookingId}/devices)

Expected action
Review and remove invalid error response codes, and better document those that are valid as to what error condition they indicate

Additional context
None