Conditional custom submission fields

[S-Haime]

Wales Press has suggested (FD 9461) to have custom submission fields that are dependent on the section selected. Currently, they have a field that is 'If submission is Y section fill in...' but they suggested it would be neat if the field would only show if section Y is selected for submission - e.g. making the field conditional depending on the section type.

(They have also requested if these could be translatable, but I believe this will be covered by currently on-going work.)