Support list of dicts

I want to accept arbitrary dicts for a field that i defined in a scheme. It seems that CKAN tries to apply some kind of sub-schema if it encounters a list of dicts. Is it possible to define such sub-schemas with this extension?
And if the fields are not known, all the data is [put into the key "__junk"](https://github.com/ckan/ckan/blob/0f145a54629287a6f7764b8fd73963bda62260ef/ckan/lib/navl/dictization_functions.py#L147-L149) as a flattened dict.

What I ended up doing is writing my own validator that gets the values out of the __junk, but I'm pretty sure this is a bad solution (see here for details: https://github.com/ogdch/ckanext-switzerland/blob/421de6c546462f0ac5764f93064d68d285addda2/ckanext/switzerland/validators.py#L39-L62).

Any ideas how to handle this?

Read CKAN's dictization_functions.py around the linked __junk handling, then compare it with the custom validator in ckanext/switzerland/validators.py. Determine how schema-defined fields should preserve arbitrary dictionaries inside lists without flattening unknown keys, and define tests that demonstrate the intended behavior.

Written by the indexing model from the issue text.