Sentinel processing does not work due to GoogleCloudAPIError. This happens in tutorial_sentinel2_ndvi.md and in tutorial_process_chain.md.

The Landsat processing in tutorial_landsat_ndvi results in KeyError. GoogleCloudAPIError will probabaly also be an issue here.

The errors are documented in: #214 Docs review.

The Landsat/Sentinel examples are also used in other documentation (e.g. actinia_core/docs/docs/introduction.md, actinia website).