feat(schema.json): make entity schemas more specific (#938)

* feat: extract helpLink

* feat: extract TextEntity

* feat(schema.json): merge ConfigurationEntity into GenericEntity

* feat(schema.json): extract TextArea entity

* feat(schema.json): extract SingleSelect entity

* feat(schema.json): extract Checkbox entity

* feat(schema.json): extract MultipleSelect entity

* feat(schema.json): extract RadioEntity

* feat(schema.json): extract FileEntity

* feat(schema.json): extract OAuth entity

* fix issues

* remove GenericEntity

* test

* Revert "test"

This reverts commit c057860.

* refactor(schema.json): add display option for LinkEntity