Close niblings (nieces & nephews)

[dpgraham4401]

Description

This PR adds the functionality to close all "Niblings" (a slang, gender-neutral term we've adopted for both nieces and nephews) of a node. So when a node is opened, if that node has siblings, the sibnling's descdants will be closed to

1. avoid the possibility of overlapping nodes (which shouldn't be a problem but this will help clean the UI looking clean and may be useful for additional functionlity in the future)
2. make it clear that one of the paths must be chosen, you can't have it both ways. We don't want to confuse users by having multiple requirements upon.

Issue ticket number and link

Checklist

• I have added tests that prove my fix is effective or that my feature works
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings