[FR] : polygon billiard from vertices

[Datseris]

It would be very convenient to have a function that takes as a input a vector of SVector{2}. This vector, call it vex will represent the vertices of a polygon billiard.

The function would then create a bunch of wall obstacles, each starting from the vertex i and ending at i+1. Optionally the function should be choosen to use FiniteWall or infiniteWall for the wall type.

The normal vector in every case should be to the right of the direction of the wall obstacle, i.e. to the right of the vector defined by end - start.

[Datseris]

This is super easily done after #183 !