ObservationCollection Properties

OMS alignment: implements the ISO 19156:2023 (OGC Topic 20 / O&M 3.0) obs-basic/ObservationCollection requirement class for sosa:ObservationCollection. This building block defines an ObservationCollection according to the SOSA/SSN v1.1 specification. It defines a set of logical rules regarding presence of mandatory properties anywhere within a potentially nested collection hierarchy. (implemented in SHACL, exploiting the semantic mapping to SOSA)