Cascade-config

Added

- Added `max_recursion_depth` argument to `CascadeConfig` to limit the depth of
hierarchically updating nested dictionaries. When the maximum nesting depth is
exceeded, the new dictionary will be used as-is, overwriting any previous
values under that dictionary tree.

Fixed

- Fix previous broken build (did not include changes)

Fixed

- Fix parsing of empty dictionaries and `False` configuration values. These would
previously be overridden by the downstream configuration.

Added

- Add none_overrides_value option. Before this change, None values would unexpectedly
override previously configured values. Now, the previous value will be retained if
newer values are None. The old behavior can be re-enabled with by setting the
none_overrides_value argument of CascadeConfig to True.

Added

- Initial release