Fields of type array

[martijnvermaat]

Was: GitLab #72

The items should probably be of type string, integer, or number. This will require some changes to our plexus form components, but in principle it should be possible.

A use case is the FAM parser .getTexts() which returns an array of multiline text fields (.getTexts()). However, they are of limited use since we cannot use their coordinates (yet?).

Not sure about any other use cases, so shouldn't be high priority probably.