Flatten yaml properties with list and map context.

[radcortez]

Proposal to flatten the yaml into config properties without losing map / list context for conversion.

The entire yaml is flatten by keeping context of any list index in the property name in the style:
for.[0].bar
for.[1].bar

This allows to read the config directly per index if the consumer knows what he wants. Additional, the key foo.bar will keep a dumped version of the original yaml so it can also be easily converted.

A few additional things can be added:

• additional flattening when a list contains only one element. either drop the index or use a specific name in the config property name.
• converters