Create Robustness test to verify performance over different source positions

[thebot002]

After the successful implementation of the model with a sub-grid defined inside the source tile (Model 2) #52 we need to implement a test that checks how the performances are impacted by moving the source to different positions both:

1. inside the source tile
2. all across the field

[thebot002]

Implemented 18th of September

Two different tests have been defined:

1. A grid test where the source is moved by 2 units along both axes up to 10 units (so 0, 2, 4, 6, and 8 units of shift from the center). This is useful to have a colormap of how well a model performs when moving the source away from the center of a tile and how it performs with a source across a macro-tile.

2. A diagonal test where the source is moved by 2 units along the diagonal of the environment. This is a useful test that will cover source positions both at the center of the cells and at the further point from the center of tiles (ie in the corner of macro-tiles). This allows a line-graph to be drawn with the performances at each point along the diagonal.