Continuation from #2314

These items need to be covered before DUO feature can be released:

• Update Manual (and changelog mention)
• Write up ADR on DUO, see rems/docs/architecture ADR 019: DUO #2848
• Implement browser tests to cover primary user stories
• DUO fields should not be editable in submitted application #2997
• perhaps approver-bot / rejecter-bot need to support DUO fields
• Probably we should add DUO codes 6 and 42
• Logic should maybe use hierarchy 1 > 42 > 6 > 7 (see DUO hierarchy)

These items are nice-to-haves:

• Refactor DUO code restriction :type - currently restriction type is used to access both restriction field type (e.g. date field or number input or basic input) and restriction translation, but for example publication moratorium uses restriction type :date which is generic field type
• Do not show DUO codes in application if no resources require DUO codes Hide DUO codes in application UI if no resources require DUO codes. #3048