Operator: 'Critical for licensing configuration' fields should be marked with dedicated decorator

[eparovyshnaya]

Dashboard explains that some model objects' fields are 'Critical for licencing configuration'.

Forms for those objects editing mark those fields as 'mandatory'.

A model object can have a potentially arbitrary set of fields that are crucial for the object instantiation. These fields are 'mandatory'.

'Critical for licencing configuration' fields are less numerous and, besides being mandatory, should also suit more strict requirements: must be readable, talkative, informative.

So the corresponding ui controls should have a specially dedicated decorator. That would be also useful for a user to achieve some textual explanation (tooltip?) advising the nice-to-have merits for such a field's value.

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Version: 0.4.0
Ported from bugs.eclipse.org: 546503
Ported from Eclipse Passage issue 960