Models being created without having names

Migrated from GitHub issue HumanBrainProject/hbp-validation-framework#286, opened by @shailesh on 2020-10-14.

On the web apps, model name is a mandatory field. But the APIs seem to allow models to be created without names. E.g.: https://model-catalog.brainsimulation.eu/#model_id.400e4aa1-bb9e-4615-ba16-dc71c44b7c2f

Note: it is presently unclear which fields are mandatory for models and tests. This has varied quite a bit over time, and so even I am a bit clueless. I mostly resort to trial and error when trying to identify mandatory fields... not ideal!

Related to: https://github.com/HumanBrainProject/hbp-validation-client/issues/86