TS 103 120 CR043 - Including link to preservation request

This contribution build on discussion of Google's contribution LI(23)P62040. In some cases, disclosure requests are related to a prior preservation request. It is helpful to be able to indicate this as part of an LDTask Object.

TS 103 120 does not currently have a way to represent preservation requests, and so it is assumed that they will occur out-of-band. The proposal below reflects that. However, in future we may wish to extend TS 103 120 to cover the transmission of preservation requests. If this happens, the proposal below allows for the later inclusion of a strongly-typed TS 103 120 reference.