Create data mapping tutorial with ASTE

[uekerman]

We regularly face the issues that users have problems with understanding the mapping configuration and how well the mapping works, in particular for RBF data mapping.

On the other hand, ASTE already has some nice features to do mappings with artificial geometries (and a demo). The only step missing is to write a nice little tutorial around that (in the preCICE wiki) and explain how to compare different mapping algorithms.

[fsimonis]

We could use this test case.

[kursatyurt]

Will be solved in https://github.com/precice/tutorials/pull/244