JSON Schema for jbang-catalog.json

[wfouche]

Create a JSON Schema for the jbang-catalog.json file used by JBang. None exist at the moment.

The schema file should be added to the jbang.dev documentation site.

[wfouche]

The IntelliJ JBang plugin has a schema file for jbang catalogs:

• https://github.com/jbangdev/jbang-idea/blob/main/src/main/resources/jbang-catalog-schema.json

[maxandersen]

??

[wfouche]

??

There is no schema file for catalogs in the main jbang github repository, but I discovered the one in the jbang-idea repository by chance. We have a schema file, creating a new one is not required.