move all test from data_regression to num_regression

[12rambau]

Earth engine is not always exporting results with the same rounded value (we are talking about the 10th decimal). This makes most of the tests very fragile.

I realized that pytest-regression is equipped with a num_regression fixture that is dedicted to compare numerical value with a default tolerance set to e-8 which would make the test more stable.

It can safely be used on every image regressions as we compute a reducer to get the datas.

nice side effect: it will reduce the size of the repository as csv are lighter than yml files.