add field productseries require for nlh-ahn to differentiate between series nlh-ahn1, nlh-ahn2, nlh-ahn35-1, etc.
  each series is stored in its own S3 bucket, but should be presented under one single product nlh-ahn
  new field productsieries helps to address the right S3 bucket

support the new NLH AHN mets Structure
  in AHN we differntiate between page based view and article based view
  instead of presenting article snippet scans (same resolution as fullpage) we decided to highlight the article on the full page
  we added new logical structure elements, one for each article (or article part, if an arcticle build up from multiple parts)
  the selection is possible from the table of contents part elements (Part 1, Part 2, etc)

additional fields:  LogFullpage, LogFullpageCoord, LogFulltextID, LogFulltext
  LogFullpage: ID of Fullpage
  LogFullpageCoord: article coordinates on the fullpage
  LogFulltextID: ID of article (logical structure element)
  LogFulltext: Fulltext of article

additional XML mappings to reflext the new structure
  mets:fptr>mets:par>mets:seq>mets:area
  mets:seq: we always have two seq elements
    the first contains the info of fullpageID and article coordinates on the page
    the second contains the fulltextID (or article scan IDs)
  mets:area are repeatable, one per article part, the seq's must take the same number of area's and the position must fit togester (relation between coor in the first seq and fulltextID) in the second seq