This is an important change in the architecture to propagate
integrations. We can now propagate instance-level integrations and
templates using batching and Sidekiq queues.

The problem before is the performance of the worst-case scenario, where
if there are no matching records and the anti-join. With the new
approach, each job in the new queues handles a batch of projects/groups;
rather than having a single job for all of them.

This is what we do right now in the complex case of propagating an
instance-level integration:
- Update inherited integrations,
- Create integration for all projects without integration.
- Create integration for all groups without integration.

BEFORE:

                 Save integration
                        ↓
            ┌┬───────────────────────┬┐
            │| Propagate integration |│
            └┴───────────────────────┴┘
                        ↓
           Update inherited integrations
  Create integration for all projects without integration
  Create integration for all groups without integration

AFTER:

                 Save integration
                        ↓
            ┌┬───────────────────────┬┐
            │| Propagate integration |│
            └┴───────────────────────┴┘
               ↓                   ↓
  ┌┬─────────────────────┬┐ ┌┬───────────────────────┬┐
  │| Propagate to groups |│ │| Propagate to projects |│
  └┴─────────────────────┴┘ └┴───────────────────────┴┘
            Update inherited integrations