Calling application version management

Add an optional field in API requests specifying the software version of the Connecting System. This could be descriptive, such as 'v1.0.5', or an ID such as a GUID that could be provided from NHSD Service Management that is linked to an approved RFC. This will benefit Connecting Systems to easily communicate what version of software is using an API as well as benefit NHSD to identify if a particular Connecting System software version is showing unexpected behaviour in API requests.