Add example on the use of dcterms:conformsTo with a catalog record

[andrea-perego]

See resolution in https://www.w3.org/2022/03/22-dxwgdcat-minutes#r02

The proposal is to add an example in §14.2.1 Conformance to a standard to show how to use dcterms:conformsTo with a dcat:CatalogRecord.

The proposal is implemented via PR #1488