Fix(ruleset): [schema] Enhance schema compliance and remove redundancies

[Karan-Palan]

This PR introduces two key improvements to the rule.schema.json and
ruleset.schema.json files to enhance their compliance and reduce redundancies:

1. JSON Schema Draft 7 Compatibility (Fixes issue The schemas follow the JSON Schema Draft 7 dialect but make use of the $defs keyword #669):

   • Updated all instances of $defs to definitions and their corresponding
     $ref pointers.
   • The $defs keyword was introduced in JSON Schema 2019-09, making it
     incompatible with the declared Draft 7 schemas. This change ensures
     schemas compile correctly with strict evaluators like Blaze.
   • This is a purely syntactic update with no semantic changes.

2. Remove Redundant 'type' Declarations with 'enum':

   • Eliminated the anti-pattern of explicitly declaring type: "string"
     alongside enum for properties in both schemas.
   • The enumeration choices inherently imply their respective types, making
     the explicit type declaration redundant.
   • This improves schema correctness, readability, and adherence to JSON
     Schema best practices.

These combined changes lead to more robust and compliant schema definitions.

Note: These auto-fixes were made with the help of sourcemeta's jsonschema cli , we are improving the linter and defining linting rules as part of a GSoC project. If helpful, I could help integrate the linter with the schemas in the repo, so it can help flag and fix redundancies and errors

[daveshanley]

Hey cool! Yeah, if you want to add schema linting, that would be great. just don't lint test specs, they can't be fixed or changed :)

[daveshanley]

Nice.

I took this from spectral's ruleset schema and modified it for my own needs, I would also go see if they need help too!

[Karan-Palan]

Hey cool! Yeah, if you want to add schema linting, that would be great. just don't lint test specs, they can't be fixed or changed :)

@daveshanley, another project named krakend uses the cli in their workflow - https://github.com/krakend/krakend-schema/blob/main/.github/workflows/validate-json-schema.yml

I'll add something like that to the project :)