Improve UIX when adding/editing a re-used FormDefinition

[Bartvaderkin]

Currently when adding a re-usable FormDefintion as FormStep it is not clear you are now editing a shared objects except for the "Is Reusable" checkbox.

There should be a warning message, or maybe the fields are blocked from editing until the user explicitly unlocks them with a button and a modal warning/explainer.

Possibly the Steps list could also have an Icon indicating it is a reused 'standard' step.

[sergei-maertens]

The form editing UI should display a warning that the form definition is used in x number of other forms, which can be clicked to display which forms in a modal. Is this broken?