Representations hierarchy: Handle fields same way as in other functions

[iLLiCiTiT]

Changelog Description

Function get_representations_hierarchy does convert fields the same way as other getter functions.

Additional review information

Implemented helper function to convert fields for each entity type which is used across all functions.

Testing notes:

1. Call get_representations_hierarchy (or get_representation_hierarchy) with e.g. folder fields containing "attrib".
2. You should get all attributes of the entity.

Resolves #212