Maps addition Ml:: graphql types

What does this MR do and why?

Maps addition Ml:: graphql types

• Adds CandidateParamType, CandidateMetricType, CandidateMetadataType
• Adds params, metrics and fields to CandidateType
• Adds packageId field to ModelVersionType

These are necessary to move the Model registry data fetching to graphql !149260 (merged)

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Numbered steps to set up and validate the change are strongly suggested.

1. In rails console enable the experiment fully

   Feature.enable(:model_registry)

2. Create a model and model_version:

   p = Project.find_by(id: 1)
   model = Ml::FindOrCreateModelService.new(p, "gitlab_amazing_model").execute
   model_version = Ml::FindOrCreateModelVersionService.new(p, { model_name: "gitlab_amazing_model", version: "1.0.0" }).execute
   candidate = model_version.candidate
   Ml::CandidateParam.create!(candidate: candidate, name: 'param1', value:  'value1')
   Ml::CandidateMetadata.create!(candidate: candidate, name: 'metadata1', value:  'metadataValue1')
   Ml::CandidateMetric.create!(candidate: candidate, name: 'metric1', value:  0.6, step: 1)

3. Open http://localhost:3000/-/graphql-explorer and run the following query (change model id for the model created):

   query {
     mlModel(id: "gid://gitlab/Ml::Model/1") {
       id
       latestVersion {
         packageId
         candidate {
           id
           name
           iid
           eid
           status
           params {
             nodes {
               id
               name
               value
             }
           }
           metadata {
             nodes {
               id
               name
               value
             }
           }
           metrics {
             nodes {
               id
               name
               value
               step
             }
           } 
         }
       }
     }
   }

   It should return something like:

   {
     "data": {
       "mlModel": {
         "id": "gid://gitlab/Ml::Model/1",
         "latestVersion": {
           "packageId": "gid://gitlab/Packages::Package/5025",
           "candidate": {
             "id": "gid://gitlab/Ml::Candidate/5000",
             "name": "hare-zebra-cobra-9745",
             "iid": 5000,
             "eid": "e9a71521-45c6-4b0a-b0c3-21f0b4528a5c",
             "status": "running",
             "params": {
               "nodes": [
                 {
                   "id": "gid://gitlab/Ml::CandidateParam/318",
                   "name": "param1",
                   "value": "value1"
                 }
               ]
             },
             "metadata": {
               "nodes": [
                 {
                   "id": "gid://gitlab/Ml::CandidateMetadata/226",
                   "name": "metadata1",
                   "value": "metadataValue1"
                 }
               ]
             },
             "metrics": {
               "nodes": [
                 {
                   "id": "gid://gitlab/Ml::CandidateMetric/46",
                   "name": "metric1",
                   "value": 0.6,
                   "step": 1
                 },
               ]
             }
           }
         }
       }
     }
   }