Add tern:SamplingCollection, an implementation of sosa:SamplingCollection

[ashleysommer]

Added tern:SamplingCollection an implementation of sosa:SamplingCollection from the recent SOSA ontology PR.
Added SHACL shapes for tern:SamplingCollection
I followed the same patterns in this one that tern:ObservationCollection uses.

The purpose of SamplingCollection is to group one or more Samplings with common properties or attributes, with the ability to hoist the shared properties to the SamplingCollection.

This is a supporting PR, showing evidence of implementation in support for the pending "SamplingCollection" PR in SOSA w3c/sdw-sosa-ssn#227

Note, I don't have topbraid composer, so I edited the tern.ttl and tern.shapes.ttl by hand for this, I couldn't export a new version of tern.ttl.txt or tern.ttl.svg or any of the html files.

[nicholascar]

Where is sosa:SamplingCollection? I see sosa:ObservationCollection in the SSN Ext but not that class...

Since a Sampling is some kind of Observation - SSN doesn't link them with upper classes but also doesn't show disjointness - perhaps we can just use Observation Collections to house Samplings.

There is already a TERN Observation Collection class defined, so if my suggestions here are followed, we don't need to do anything.

[ashleysommer]

Sampling collection is still in PR: w3c/sdw-sosa-ssn#227
They may need to see one more profile or implementation to get it over the line.