Gaps can be made in the universal tree's hierarchies

[rrowlands]

Certain hierarchies in the universal tree (political, urban, spray) do not allow universals to join the hierarchy if their parent universal is not part of the hierarchy as this would create a gap.

However, a new universal can be created in the middle of one of these hierarchies and does not automatically join the hierarchy creating a gap. This presents no error or warning but causes downstream issues such as #4038 and #4064.

When creating a new universal, If parent universal and any child universal are part of one or more hierarchies that do not allow gaps, then newly created universal should be added to those hierarchies.