DAT-2380 Remove Holmes i.e. ArticleType  to reduce timeouts on indexer

this PR is mirrored #5828 

This change is only backend change that removes indexing of article_type through our old process.
The new indexing pipeline is handling that right now. 
Currently indexing article type causes spontaneous timeouts when asking service for article type.
Where is that handled in the new approach (link is enough)