Add divide Attribute to Manage Watering Time and a Service to Modify Repeats

[FermedePommerieux]

It would be beneficial to have the ability to divide the watering time when we repeat a watering sequence instead of multiplying it. When setting the watering time via smart_irrigation, we typically define the total time for a zone or sequence. To conserve water, it would be useful to have a specific behavior that allows us to divide the defined watering time by the number of repetitions instead of multiplying it.

Additionally, it would be very useful to add a service that allows modifying the number of repetitions dynamically.