Fuse has an option FUSE_POSIX_ACL which needs to be opted in by fuse server to enable posix ACLs. Add virtiofsd option '--posix-acls ' to let users enable posix ACLs support, and the compatibility options '-o posix_acl/no_posix_acl'. Closes #33 --- https://gitlab.com/virtio-fs/virtiofsd/-/merge_requests/95