Allow setting fields as required in App Within Minutes (AWM) apps / add a validation mechanism

It is currently not possible to set fields as required easily / to define a validation regex or other means to validate data.

A validation mechanism / a way to mark a field as required would be nice. The validation should also happen server-side.

Potential workaround (client-side only):

• write a custom displayer for the concerned fields adding a required attribute (be careful that this displayer won't be overwritten)
• add a required attributes to relevant fields using a JSX