Handle gmx:MimeFileType in onlineResource

[etj]

CKAN CSW parser only extracts a CharacterString child from gmd:CI_OnlineResource/gmd:name.

When a gmx:MimeFileType is used instead, we may use both the text() and the type.

E.g.:

<gmd:CI_OnlineResource>
   <gmd:linkage>
      <gmd:URL>http://159.213.89.76/geonetwork/srv/en/resources.get?uuid=a911afd6-241d-4087-9739-2a81f5c51ba4&fname=strade_provinciali_prato.zip&access=private</gmd:URL>
   </gmd:linkage>
   <gmd:protocol>
      <gco:CharacterString>WWW:DOWNLOAD-1.0-http--download</gco:CharacterString>
   </gmd:protocol>
   <gmd:name>
      <gmx:MimeFileType xmlns:gmx="http://www.isotc211.org/2005/gmx" type="application/x-compressed">strade_provinciali_prato.zip</gmx:MimeFileType>
</gmd:name>
   <gmd:description>
      <gco:CharacterString>File zip contenente lo shape file del dato</gco:CharacterString>
   </gmd:description>
</gmd:CI_OnlineResource>