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- Add ERA5 support (download, reading, TS conversion)
- Add netcdf support for ERA5 and ERA-Interim download (regular grid)
- Add new grid defintions: netcdf download in regular grid, grib in gaussian grid
- Add Download with spatial resampling (grib and nc)
- Update GRIB message storing (per day instead of per message)
- Add tests for splitting downloaded files, ERA5 reading, ERA5 reshuffling, generated grids
- Add new test data