Refactor s3fs (and the aotbotocore) out as a dependency

[stijnvanhoey]

s3fs is a convenient package to interact with s3 (feels like coding against normal file system), but since s3f3 relies on the async aiobotocore package some issues arised:

• due to very strict dependencies in both boto3 and aiobotocore, the pip solver was not able to solve this unless defining boto3 as an additional install from s3fs (see https://github.com/enram/vptstools/commit/daeb285d949c84071a1c9641ef9d07e241c9f0d0 for fix)
• aiobotocore requires raw_headers which are not according to specs in the moto-library used in the testing (see https://github.com/getmoto/moto/issues/3259 for description and https://github.com/enram/vptstools/commit/802b9f5a94c39b488d492908289b1ff65aa136e8 for the fix)
• aiobotocore/s3fs keep in an recursive loop copy-pasting the files in the pytest-context leasing to an ever increasing file size when running the tests. Has been solved by relying on boto3 instead for the download, see https://github.com/enram/vptstools/commit/28a5e42540b06118c4584940bde4f96d75d1917c

Hence, these issues have been handled in https://github.com/enram/vptstools/tree/SVH-country-filter, but I'm not sure if the convenience of s3fs is worthwhile having it as a dependency. It might be that excluding s3fs would make things easier to maintain.