Create an "update parent" mutation

[vnugent]

Use case

I want to move an area to be under a different parent.

To do:

• [ ] Update parent id
• [ ] Update path tokens (look at area renaming code for ways to recursively update children's paths)
• [ ] Update ancestors
• [ ] Unit test

[CocoisBuggy]

I've been needing this for a while and have decided to tackle it in connection with another feature I am needing - which would benefit greatly from knowing how group structures are changed and validated.

I will create a PR soon, but the gist is that I am going to add a new field to the area collection by the name of 'parent'. This is the source of truth from which

• path tokens
• ancestors
• children

will be derived (Not to mention my other structure hierarchy query will be able to run 2-4x faster through the mongo pipeline)