Change `rdfs:label` to `dct:description` for representation of potenitally long texts

[jakubklimek]

Problem statement rdfs:label is used for potentially long texts where dct:description might be a better fit.

Note that there was a Dublin Core usage guideline for using rdfs:label in 2002, but was deprecated in 2008 in favor of rdf:value.

Example from Provenance Statement:

[] a dct:ProvenanceStatement ;
  rdfs:label """
    The raster data sets have been created out of the Noise Spatial Database, 
    which in turn contains all versions delivered by the relevant countries 
    (EU and EFTA) to Reportnet (CDR). The data from Reportnet is automatically 
    incorporated into the database, with the exception of those data sets which 
    require a manual review (due to problems with naming conventions or 
    Coordinate Reference System). The data set covers any submission by the 
    countries until 01/01/2019.
  """@en .

The places where rdfs:label mappings are used for potentially long texts:

• Rights statement text
• Provenance statement text
• License text - to be removed in #113

Proposal Change the mappings to dct:description.

[jakubklimek]

Approved during the webinar.