Wrap method parameters in a struct in the BLS Aggregator Service

[damiramirez]

PR adds a new methods in the BLS Aggregator Service.

• We should create a struct to store task information such as logger, task_index, aggregated_response_sender, current_aggregated_response, etc. (Check handle_task_expired params)

The following methods receives a large number of parameters, which is why we’re using #[allow(clippy::too_many_arguments)].

• loop_task_aggregator
• handle_new_signature
• build_aggregated_response

The idea is to create a new struct to encapsulate all these parameters.