Add redis counter for manifest delete events

What does this MR do and why?

Closes #382568 (closed)

In !112539 (closed), we learned that the container_registry does not send in an actor for manifest delete events. There is still some work done for the actor to be sent so we discussed and pivoted to a solution for now.

In this MR, we implement the new plan to count the manifest delete events using a simple Redis counter without attributing it to any user.

How to set up and validate locally

1. Test that the ContainerRegistryEventCounter is registered:

pry(main)> Gitlab::UsageDataCounters::ContainerRegistryEventCounter.totals
=> {:container_registry_events_i_container_registry_delete_manifest=>0}

2. Call the endpoint The counters are increased when container_registry calls the endpoint. We can test the counters by simulating a call to the endpoint.

To be able to curl without any tokens,

• open api/container_registry_event.rb and
• comment out the line before { authenticate_registry_notification! }

curl -d '{
    "events": [
      {
        "id": "a582a0f3-e620-43e6-8e98-ff850fc9d984",
        "timestamp": "2023-01-25T14:45:54.17327+11:00",
        "action": "delete",
        "target": {
          "mediaType": "application/vnd.docker.distribution.manifest.v2+json",
          "size": 528,
          "digest": "sha256:af06af3514c44a964d3b905b498cf6493db8f1cde7c10e078213a89c87308ba0",
          "repository": "group-a/project-a",
          "length": 528,
          "url": "http://registry.test:5000/v2/root/test/manifests/sha256:af06af3514c44a964d3b905b498cf6493db8f1cde7c10e078213a89c87308ba0"
        },
        "request": {
          "id": "8ef8d69b-f957-45ab-ba2c-9153291f47b6",
          "addr": "172.16.123.1:56969",
          "host": "registry.test:5000",
          "method": "PUT",
          "useragent": "docker/20.10.18 go/go1.18.6 git-commit/e42327a6d3c55ceda3bd5475be7aae6036d02db3 kernel/5.15.68-0-virt os/linux arch/arm64 UpstreamClient(Docker-Client/20.10.22 \\(darwin\\))"
        },
        "actor": {
          "name": "root",
          "user_type": "personal_access_token"
        },
        "source": {
          "addr": "127.0.0.1:5000",
          "instanceID": "45681f21-a006-42f2-ab7c-4cc37d8906b4"
        }
      }
    ]
  }' -H "Content-Type: application/vnd.docker.distribution.events.v1+json"  -X POST  'http://gdk.test:3000/api/v4/container_registry_event/events'

3. Test that the counter has been incremented

[4] pry(main)> Gitlab::UsageDataCounters::ContainerRegistryEventCounter.totals
=> {:container_registry_events_i_container_registry_delete_manifest=>1}

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 #382568 (closed) Related to !112539 (closed)