Add GraphQL fields for Catalog resources

What does this MR do and why?

This MR adds the basic structure for fetching CI catalog resources using GraphQL. It adds a Ci::Catalog::ResourceType, a Resolvers::Ci::Catalog::ResourceResolver, and a ci_catalog_resources field to QueryType.

Screenshots or screen recordings

How to set up and validate locally

1. In the Rails console, run Feature.enable(:ci_private_catalog_beta)
2. Choose a namespace with at least one project. Find that project's ID
3. In the Rails console, create a CI catalog resource with:

   ::Ci::Catalog::Resource.create(project: Project.find(<project_id>))

4. In /-/graphql-explorer, use this query:

   query {
     ciCatalogResources(projectPath: "<project_path>") {
       count
     
       nodes {
         description
         icon
         name
       }
     }
   }

5. See that you get the expected catalog resource. The name and description should match the name and description of the project. The icon should be the avatar path of the project.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #393567 (closed)