Add dependency proxy to graphql

🐟 What does this MR do?

Adds dependency proxy types and fields to GraphQL. The dependency proxy is a group-level feature, so these are accessible through the group type.

🎞 Screenshots or Screencasts (strongly suggested)

🎣 How to setup and validate locally (strongly suggested)

1. Set up the dependency proxy with GDK

2. Create a group

3. Pull a few images through the group using the dependency proxy

4. Query the data:

    query {
      group(fullPath: "<your-group-full-path>") {
        id,
        dependencyProxyBlobCount
        dependencyProxyImageCount
        dependencyProxyTotalSize
        dependencyProxySetting {
          enabled
        }
        dependencyProxyManifests {
          nodes {
            fileName
            imageName
            size
            createdAt
            updatedAt
            digest
          }
        }    
        dependencyProxyBlobs {
          nodes {
            fileName
            size
            createdAt
            updatedAt
          }
        }
      }
    }

🐘 Database

Queries

Click to expand

When querying for dependencyProxyBlobCount

SELECT COUNT(*) FROM "dependency_proxy_blobs" WHERE "dependency_proxy_blobs"."group_id" = 9970

Explain plan 4.404 ms: https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/6122/commands/20684

---

When querying for dependencyProxyImageCount

SELECT COUNT(*) FROM "dependency_proxy_manifests" WHERE "dependency_proxy_manifests"."group_id" = 9970

Explain plan 16.635 ms: https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/6122/commands/20685

---

When querying for dependencyProxyTotalSize

SELECT SUM("dependency_proxy_manifests"."size") FROM "dependency_proxy_manifests" WHERE "dependency_proxy_manifests"."group_id" = 9970
SELECT SUM("dependency_proxy_blobs"."size") FROM "dependency_proxy_blobs" WHERE "dependency_proxy_blobs"."group_id" = 9970

• Explain plan 1 (manifest sum) - 1.1 ms: https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/6122/commands/20710

• Explain plan 2 (blob sum) - 241ms: https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/6122/commands/20687

---

When querying for dependencyProxySetting

SELECT "dependency_proxy_group_settings".* FROM "dependency_proxy_group_settings" WHERE "dependency_proxy_group_settings"."group_id" = 9970

Explain plan 4.107 ms: https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/6122/commands/20688

---

When querying for dependencyProxyManifests

SELECT "dependency_proxy_manifests".* FROM "dependency_proxy_manifests" WHERE "dependency_proxy_manifests"."group_id" = 9970 ORDER BY "dependency_proxy_manifests"."id" DESC LIMIT 100

Explain plan: 1.677 ms: https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/6122/commands/20722

---

When querying for dependencyProxyBlobs

SELECT "dependency_proxy_blobs".* FROM "dependency_proxy_blobs" WHERE "dependency_proxy_blobs"."group_id" = 9970 ORDER BY "dependency_proxy_blobs"."id" DESC LIMIT 100

Explain plan: 2.753ms: https://console.postgres.ai/gitlab/gitlab-production-tunnel-pg12/sessions/6122/commands/20717

📐 Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• [-] I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• [-] I have tested this MR in all supported browsers, or it's not needed.
• [-] I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.

Security

Does this MR contain changes to processing or storing of credentials or tokens, authorization and authentication methods or other items described in the security review guidelines? If not, then delete this Security section.

• Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team

Related to #322839 (closed)