0003-new-config-files.md needs update

[zmstone]

New Config Syntax section should be referring to 0002.
YAML has been declined, so we should not mention that.

[zmstone]

### Deploy With Centralized Config Service we are most certainly not going to do this in one go.

So please break the proposal down to more manageable small steps.

[zmstone]

For #### Config Specs
I think we'll need to stick with cuttlefish schema for a while.
maybe extending the schema file instead ?