Add custom editor for assessmentDefinitions fields

[maradragan]

Currently the configuration of an assessment requires quite a technical person and also requires knowing the schema for the assessment fields.

It would be better to have a special type of field, using a custom editor for assessment configuration type of fields. This way it will be less error prone and easier to add/change assessments.

[cemalettin-work]

Currently we are storing / parsing custom fields with a shape like object of objects, we need to add a new field type to anet-schema.yml to allow that. Also create custom field components for object of objects