Documentation does not reflect ADR007

[KevinCathcart]

The documentation, does not fully reflect ADR007.

My understanding of the result of ADR0007 is that normal integrations should not be extending PLATFORM_SCHEMA, but should be using CONFIG_SCHEMA instead, at least for any integrations still allowed to use YAML configuration given ADR0010.

Yet the Platform checklist still suggests using PLATFORM_SCHEMA, as does the the Component Checklist.