frontend: The line left by the vehicle's path should be erasable or have a fade-by-timeout

[ArturoManzoli]

Current behaviour

The yellow line left by the vehicle's path is accumulating and making the map visually overloaded.

Expected or desired behaviour

The path shouldn't accumulate on the map. It could have a clear button or a time-to-fade could be set to define its lifetime.

Prerequisites

• I have checked to make sure that a similar request has not already been filed or fixed.

[joaoantoniocardoso]

It could also fade transparently, making it easier to distinguish a new path from an older one.