Support JSON/YAML format for config

**Is your feature request related to a problem? Please describe.**
It's hard write configs without having any sort of intellisence. YAML/JSON files have good enough [LSP](https://marketplace.visualstudio.com/items?itemName=redhat.vscode-yaml) for VS Code:


**Describe the solution you'd like**
Add support for JSON/YAML formats for config until ron gets intellisence support like JSON/YAML where user can create any arbitrary schemas and associate them with any files.

**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.

**Additional context**
Besides, I am suggesting this feature as I [can](https://github.com/SchemaStore/schemastore/pulls/EmilySeville7cfg) write JSON schemas and could add a new one for yours config if JSON/YAML formats were supported.

El issue no menciona archivos, pruebas ni puntos de entrada. Empieza por localizar cómo lee actualmente gitui la configuración y determina los formatos JSON/YAML previstos y el comportamiento de asociación de esquemas; se considera terminado cuando ambos formatos sean compatibles con la inteligencia del editor solicitada.

Escrito por el modelo de indexación a partir del texto del issue.