Update model generation to relational models.yml

[jsangmeister]

part of #2311

[r-peschke]

As first step use the recommendation for checking field or not field. But I think we will replace this by functionality from the generation of relational db schema.

[jsangmeister]

Tests are failing because motion/identical_motion_ids is still modelled as a number[] field because the current generate script cannot handle this case. This has to be changed before the tests here can succeed.