Expand API to indicate which fields are required

Problem/Motivation

Instead of simply indicating in the field's description whether an element is required, have an option in the APIs that indicate the element is required, and then provide indications in the UI that they're required. Because we want to allow the form to be closed so additional fields can be added, etc, don't make this a hard requirement, more of a soft requirement. It may also be useful to validate the settings when the display is opened or saved.

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes