feat: API changes to support cancelling tasks

[timclifford]

Checklist

• Affected Issues have been mentioned in the Closing issues section
• Documentation has been written/updated
• PR title is ready for changelog and subsystem label(s) applied

This adds support to the API to be able to cancel tasks. There is a permission split to do by production and development environment, and the roles are configured by default to be developer can cancel development environment tasks, and maintainer can cancel production and development environment tasks.

The cancelTask mutation can be called like so

mutation cancelTask {
  cancelTask(input:{
    task: {
      taskName: "lagoon-task-pt2pp5"
      environment: {
        id: 3
        project:{
          id: 18
        }
      }
    }
  })
}

Changes to the UI will be required to support the cancellation of tasks in https://github.com/uselagoon/lagoon-ui

Closing issues

closes #3106

[shreddedbacon]

I like, but theres some things I think we can do better to better handle cancelling tasks (the controller needs to be updated too, but we should add the initial support into core before we expose task cancelling in the api)

[rocketeerbkw]

Would close #3106

[tobybellwood]

Now that the controller can cancel tasks - the approach needs revisiting. @shreddedbacon to assess refactor/rewrite

[bomoko]

Looks good, and should all work - just added a couple comments/questions. Nice PR!