[EDGES] Support edge directionality in transit

[adamocarolli]

On larger graphs it becomes hard to see the directionality of edges in-flight. There are too many edges and nodes that being able to trace each edges source/target is very difficult.

A possible approach is to support a variation of this animated trip edge type as it provides directionality without the requirement of seeing the source/target.

See (https://deck.gl/examples/trips-layer/):

This issue is opened to discuss possible ways of displaying directionality on larger graphs

[adamocarolli]

@RosaRomeroGomez mentioned tapered edges as a possible option. See edges on right: https://www.scitepress.org/Papers/2017/61023/61023.pdf