AT:

• migration so all types have been replaced by _doc
• all type parameters are replaced to use default value in Elasticsearch requests

Context:
Have a look at the removal of types announcement. in 7.0 Elasticsearch will by default only use one type (_doc), which implies that we don't have to transform our indcies to that type and also can get rid of the type parameter in the requests. In 8.0 the types will even be completely removed.