Schema for config.yml

[cshaa]

Right now, setting up config.yml without intellisense kind of sucks. It would be great if Decap CMS maintained a JSON schema closely matching the config.yml docs, which could be loaded via yaml-language-server and used to provide type checking and intellisense.

[cshaa]

I quickly put together an example schema, here. If the devs here don't want to maintain the schema, I'll publish it on https://schemastore.org/, but that way it could easily get out of sync with the repo.

[bmackinney]

Related: #7006 There's another schema here: https://github.com/talves/json-schema-validator-example/blob/main/schema.json

The schema should be reflected from the source, not hand-written from the docs repo.