Add listacl listpolicy

[marsteg]

I added some very simple commands to list the Policy and ACL. It seems like it's almost a design decission that this wasn't there... but since I missed it, i thought maybe others find it useful, too.

Example Usage: python3 s3cmd -c ceph.cfg listacl s3://test3 python3 s3cmd -c ceph.cfg listacl s3://test3/test.txt python3 s3cmd -c ceph.cfg listpolicy s3://test3

I was only able to test this on ceph unfortunately.