Remove example for Media Type as it is confusing

[jakubklimek]

Problem statement
The Example for Media type is confusing:

[] a dcat:Distribution ;
  dct:format [ a dct:MediaType ;
      rdfs:label "Geopackage" ] .

1. It shows dct:format, which must be used with the File Type EU NAL, i.e. it cannot be used like this with a blank node.
2. The range of dct:format is not dct:MediaType, but dct:MediaTypeOrExtent.

The examples should be given for usages of Media Type in properties, not for the Media Type itself, as the actual recommended approach is to use the Media Type IRI, not its representation as a blank node.

Proposal

1. Delete this example.
2. Add an example for dct:format and dcat:mediaType