Overhaul core Tracker: refactor tests (remove duplicate code)

[josecelano]

Parent issue: #1181

The following code code is repeated many times in tests. It's the initialization of the application services.

let cfg = Arc::new(ephemeral_public());
let config = &cfg.http_api.clone().unwrap();

let ban_service = Arc::new(RwLock::new(BanService::new(MAX_CONNECTION_ID_ERRORS_PER_IP)));
let (stats_event_sender, stats_repository) = statistics::setup::factory(cfg.core.tracker_usage_statistics);
let stats_event_sender = Arc::new(stats_event_sender);
let stats_repository = Arc::new(stats_repository);

initialize_global_services(&cfg);

let database = initialize_database(&cfg);
let in_memory_whitelist = Arc::new(InMemoryWhitelist::default());
let whitelist_authorization = Arc::new(whitelist::authorization::Authorization::new(
    &cfg.core,
    &in_memory_whitelist.clone(),
));
let whitelist_manager = initialize_whitelist_manager(database.clone(), in_memory_whitelist.clone());
let db_key_repository = Arc::new(DatabaseKeyRepository::new(&database));
let in_memory_key_repository = Arc::new(InMemoryKeyRepository::default());
let _authentication_service = Arc::new(service::AuthenticationService::new(&cfg.core, &in_memory_key_repository));
let keys_handler = Arc::new(KeysHandler::new(
    &db_key_repository.clone(),
    &in_memory_key_repository.clone(),
));
let authentication = Arc::new(authentication::Facade::new(&keys_handler));

let tracker = Arc::new(initialize_tracker(&cfg, &database, &whitelist_authorization, &authentication));

We now have the AppContainer and it's initialized here.

The initialization is not exactly the same in all tests because in some tests some services are not needed or mocked. However I think we can extract a simple abstraction or even a builder in the future. For now, I'm just going to remove the duplication as much as possible.