Add class annotations for SAMPO-UI

[SvenLieber]

In order to get facet classes for SAMPO-UI we have to introduce new classes. When using a generic class like schema:CreativeWork we would retrieve all translations and all originals for example. Among others this is also because we can't work with named graphs in the SAMPO-UI configuration, only in the underlying SPARQL queries to a certain extent.

We already introduced the new classes

• schema:CreativeWork (language and time period criteria, based on ETL pipeline from different data sources)
• btm:BeltransTranslation (language, time period and nationality criteria)
• btm:BeltransGenreTranslation (only genre criteria)
• when querying a combination of the above we can retrieve all translations that were studied by the BELTRANS PhD students

Translations that are part of the SAMPO-UI interface are based on the first class.
Similarly we need classes for the original view

• schema:CreativeWork (language and time period criteria, created based on all schema:CreativeWork of translations)
• btm:BeltransOriginal (language, time period and nationality criteria)
• btm:BeltransGenreOriginal (only genre criteria)

If we need more specific classes or properties, this issue should be updated!