Changes
* Add content to docs (28) tilen1976
* Poetry dependencies (27) tilen1976
* Rename and add folders (26) tilen1976
* Added default value for the statistic subject url (25) Jorgen-5
* Add CODEOWNERS (24) mmwinther
* Added Null check for statistic subject url (23) Jorgen-5
* Simplify merge of metadata (22) Jorgen-5
* Update readme (21) mmwinther
* Simplified _extract_metadata_from_files (20) Jorgen-5