Define schema configuration for mapping instead of sequence

I've tested this locally and you need to change the layout_paragraphs_restrictions.settings to follow the mapping schema. The main difference would be replacing something like,

highlight_stack_components:
context:
parent_type: highlight_stack
components:
- highlight_box

With,

highlight_stack_components:
context:
parent_type: highlight_stack
components:
highlight_box: { }

The difference would be replacing `- highlight_box` with `highlight_box: { }`.

I think we can change configurations like this where `- something` would be replaced with `something: { }`.

I've attached a patch to test with.