Add utility functions for working with nested dictionary keys.
Review Request #12811 — Created Jan. 26, 2023 and updated
A pattern that crops up from time to time is the need to work with
nested dictionary keys, setting or retrieving something deep in a
dictionary while handling type conflicts and avoiding unwanted
alteration of data.
This will soon be used by
SiteConfigurationto help avoid some
problems when working with namespaced settings.
Unit tests passed.
Tested this along with some upcoming changes that make use of it.