Field for dynamic schema inheritance

[stevenle]

Description

The use case we're trying to solve is to give content editors the ability to generically override fields if certain conditions are met.

Something like:

overrides:
array of:
- key: the deepkey of the field to override
- value: value to replace
- conditions: some boolean conditions for applying the override

This is useful for managing regional overrides - in some cases, a content editor may need to edit a string, an asset, a component, or an entire module based on the region that a user is visiting from.

We need some way for a content editor to specify a "deepkey" and the editor automatically grabs the schema definition for that field and renders it in the doc editor.

Maybe something like schema.dynamicField() (admitedly this isn't a great name) - the content editor would be prompted to provide a "deepkey" and when the deepkey is entered (if valid), then the field would render the corresponding field for that key.