feat(schema): schema changes for custom REST endpoints

[kkedziak-splunk]

Issue number: ADDON-76812

PR Type

What kind of change does this PR introduce?

• Feature
• Bug Fix
• Refactoring (no functional or API changes)
• Documentation Update
• Maintenance (dependency updates, CI, etc.)

Summary

Changes

Schema changes required for the future feature for adding custom REST endpoints.

This change adds new options section with restHandlers.

{
  "meta": {},
  "pages": {
    "configuration": {},
    "inputs": {},
    "dashboards": {}
  },
  "alerts": [],
  "options": {
    "restHandlers": []  // <--- here 
  }
}

The array above consists of entries of the following form (example):

{
  "endpoint": "some_endpoint",
  "handlerType": "EAI",
  "registerHandler": {
    "file": "my_handler.py",
    "actions": ["list", "create", "edit", "remove"]
  },
  "requestParameters": {
    "create": {
      "some_param": {"type": "string"},
      "other_param": {"type": "number"},
      "other_param_nullable": {
        "type": "number",
        "nullable": true,
      }
    },
    "list": {
      "array_param": {
        "type": "array",
        "items": {"type": "string"},
      },
      "obj_param": {
        "type": "object",
        "properties": {
          "key": {"type": "string"},
        }
      }
    }
  },
  "responseParams": {
    // similar to requestParameters
  }
}

• endpoint - it denotes the URL path that handler is connected to
• handlerType - currently only EAI is specified here, to denote, that only EAI endpoints are supported. This is added in case we would like to support other handlers as well in the future.
• registerHandler - optional. If specified, it registers the handler in web.conf and restmap.conf.
• requestParameters - an object with action name as a key and value being a dictionary containing keys (parameter names) to values (OpenAPI data types).
• responseParameters - similar to the above one

The data types are based on OpenAPI data types.
Example data types:

• {"type": "string"}
• {"type": "number", "nullable": true}
• {"type": "boolean"}
• {"type": "array", "items": {"type": "string"}}
• {"type": "object", "parameters": {"some_param": {"type": "string"}}}
• {"anyOf": [...]}
• {"allOf": [...]}

User experience

No changes to the current user experience.

Checklist

If an item doesn't apply to your changes, leave it unchecked.

• I have performed a self-review of this change according to the development guidelines
• Tests have been added/modified to cover the changes (testing doc)
• Changes are documented
• PR title and description follows the contributing principles