Extract preprocessor steps to allow for better re-use in VS
Currently the preprocessor in VHR18 is very specific for the use of the products/collections of that project. For the use in VS, the implementation needs to be generalized.
In order to generalize the preprocessor, the necessary steps can be extracted:
- Data retrieval: download from the swift object storage (maybe abstract this to allow other sources in the future as well)
- Unpacking: (recursively) unpack downloaded source files
- File selection: from the unpacked files, select the ones that actually have significance in VS (data files and metadata files)
- Data file merging: stacking bands if separated into multiple files, combine tiles into a single file, etc
- Output data file generation: COGs (possibly others)
- Metadata extraction
- Upload to output swift bucket (maybe other object storages in the future)