Provide ccplugin to test s3 storage configuration
It would be nice to have a ccplugin that makes it easier to test if an s3 storage configuration is correct.
cubicweb-ctl s3-test instance would create a file, so some checks on it, and then remove it
I don't know if it could be in two steps so that the user can go and look at the bucket and see the
cubicweb-hello-world.txt file exists and then go back and have another command to remove the test.