rgw_user: Create RGWUser class.

Signed-off-by: caleb miles <caleb.miles@inktank.com>

Conflicts:

	src/rgw/rgw_string.h
rgw_user: general cleanup.
rgw_admin: Use RGWUser class.

Signed-off-by: caleb miles <caleb.miles@inktank.com>
cli-tests: remove output for compilation
radosgw-admin: Teuthology fixes.

Signed-off-by: caleb miles <caleb.miles@inktank.com>