Logging to a file is now working properly. Starting the EnPT processing pipeline via CLI argument parser is now working.

- added config options 'output_dir' and 'working_dir'

Added io.reader.Solar_Irradiance_reader().
Added model.srf.py for handling spectral response functions + test_srf.py.
Extended metadata reader with srf and solar_irrad attributes.
Refactored TOARad2TOARef_Transformer to Radiometric_Transformer.
Removed deprecated dummy TOARef transformer.

Replaced delimiter in Earth_Sun_distances_per_day_edited__1980_2030.csv.
Bugfix test_l1b_reader.py.

Added test_controller.py.
Added config parameters 'path_l1b_enmap_image' and 'path_l1b_enmap_image_gapfill'.
EnPTConfig is now passed to L1B_Reader and all processors.
Fixed EnPTConfig.absPath().
Replaced Earth_Sun_distances_per_day_edited.csv with Earth_Sun_distances_per_day_edited__1980_2030.csv.

Added earth sun distance and solar irradiance models (new folder "resources").
Added new module "options":
    - added config module
    - added options_default.json
    - added options_schema.py

Moved _EnMAP_Image.mask_nodata and _EnMAP_Image.calc_mask_nodata to EnMAP_Detector_MapGeo. Fixed some 'DRY' issues in metadata objects.

Revised object structure of image and metadata objects and removed separate objects for VNIR and SWIR.

Updated __version__ and __versionalias__.