Add Swarming service for Remote Task Gate

[jardondiego]

Add remote task service for Swarming and include it in Remote Task gate logic.

Summary
This PR integrates Swarming as a first-class remote task execution service within the RemoteTaskGate. It introduces the SwarmingService, which encapsulates the logic for pushing uworker main tasks to Swarming, and updates the
RemoteTaskGate to utilize this service for unified task distribution.

Key Changes

• New SwarmingService Implementation: Added a new service that implements the RemoteTaskInterface. It handles task creation by pushing them to Swarming using
  swarming.push_swarming_task, providing a standardized interface consistent with Kubernetes and GCP Batch services.
• RemoteTaskGate Integration & Refactoring:
  • Service Map Expansion: Added SwarmingService to the internal service map of RemoteTaskGate.
  • Unified Batch Task Handling: Refactored create_utask_main_jobs to delegate task creation to SwarmingService when the SWARMING_REMOTE_EXECUTION feature flag is enabled. This simplifies the logic by allowing the SwarmingService to
    filter and process swarming-eligible tasks and return the remaining tasks for distribution to other backends.
  • Single Task Routing: Updated create_utask_main_job to explicitly route swarming-eligible tasks to the SwarmingService.
• RemoteTaskAdapters Update: Added SWARMING to the RemoteTaskAdapters enum. This allows for dynamic control of its execution frequency via feature flags, matching the behavior of other remote execution platforms.

[IvanBM18]

LGTM

[javanlacerda]

Overall looks good, and I think we can merge it once some minor fixes are addressed, and then we can make the other adjustments in the following PRs.

We just need to be sure that the changes will not have any side effect in prod.

[javanlacerda]

I think we could keep this function cleaner if we could move this logic to an auxiliary function.

[jardondiego]

I am not sure I see an auxiliary function with this single line. I guess I probably do not understand very well what would we encapsulate in that auxiliary function. Can you clarify?