Sync data improvements
This is basically an upgrade of Data Spaces to improve support of generic S3 storage endpoints.
I've also added the possibility to specify the environment variable SPACES_CONFIG in the Makefile, and added this to the CI environment. This way we point it to a local mirror of our S3 storage running on Hetzner rather than Digital Ocean when running tests, to avoid using expensive bandwidth from Digital Ocean.
Edited by Øyvind Evju