show the unit of a question next to the answer field

[MyPyDavid]

Rationale / Begründung

Currently, a unit can be assigned to a question, however, the unit is not shown during the interview except if it is mentioned in the help text.

Affected

Users, Managers

Minimal functionality

• when a question has defined a unit, then, as a default, it should be shown next to the answer field

References / Verweise

• https://github.com/rdmorganiser/rdmo/blob/dbdcc1f2eb6e033e377898a8bf198282f82813c1/rdmo/questions/models/question.py#L235