Unify whitespace and punctuation usage in dcat.ttl

[jakubklimek]

While working on the Czech translation of dcat.ttl, I noticed that the punctuation and whitespaces in literals are not unified.
In general, there are three main properties used, rdfs:label, rdfs:comment and vann:usageNote. There should be a clear guideline on whether each of the literals referenced by these properties should or should not end with a full stop "." and whether or not whitespaces such as newlines are OK in the literals or not.
At the moment, these differ in various languages.

My proposal:

1. rdfs:label - should not end with a full stop
2. rdfs:comment and vann:usageNote - should not end with a full stop when it is not a full sentence. Otherwise, it should end with a full stop.

Regarding whitespaces, I would not use them in RDF Literals as this would add additional complexity to any software actually displaying those texts.
An example with whitespace padding and newlines:

vann:usageNote """This class is optional and not all catalogs will use it. It exists for 
            catalogs where a distinction is made between metadata about a dataset and 
            metadata about the dataset's entry in the catalog. For example, the publication 
            date property of the dataset reflects the date when the information was originally 
            made available by the publishing agency, while the publication date of the catalog 
            record is the date when the dataset was added to the catalog. In cases where both
            dates differ, or where only the latter is known, the publication date should only 
            be specified for the catalog record. Notice that the W3C PROV Ontology allows 
            describing further provenance information such as the details of the process and the 
            agent involved in a particular change to a dataset."""@en ;