preprocessor stac output
- creates minimalistic stac item with assets as output of preprocessor
- allows to set multiple xpaths for preprocessor config picking, using the first one actually configured and found
- remove /data mount from dev stacks
- add pansharpening preprocessing configurations for emg* collections
- add band index -> band name mapping for all so far created preprocessor configs, except core12
- add initial preprocessing updates with regarding to SAR preprocessing