Add E2E tests

[josecelano]

We are not covering the bootstrapping of the app because we use a lot of "spwan". It would be convenient to write some E2E tests for basic features like the following:

• Call the healthcheck endpoints
• Make an announce request using the HTTP tracker
• Make an announce request using the UDP tracker

We can use the docker image like in the Index.

Subtasks

• E2E tests: scaffolding #634
• E2E tests: Improve E2E test runner #647
• Tracker Checker: console command to run tracker checks #637

[josecelano]

We now run all checks:

• UDP tracker: announce and scrape requests.
• HTTP tracker: announce and scrape requests.
• HealthCheck: request to the health checker endpoint.