Alignment to SOSA/SSN

Affects: SAREF

Situation: The TS document contains an alignment to oneM2M base ontology, but not to SOSA/SSN.

Proposal: Discuss the alignment with with SOSA/SSN and add in a section after the oneM2M alignment

Status: agreed during SmartM2M-RG Meeting about 2 NWIs SAREFv3 and SAREF Com Framework V2 2019-04-08 SAREF4Indus and SAREF4Agri already propose mappings, they may be used as starting points