rgw: add checksum type and algorithm in S3 APIs#712

sungjoon-koh wants to merge 3 commits intoceph:masterceph/s3-tests:masterfrom

sungjoon-koh:wip-s3-cksum-type-algosungjoon-koh/s3-tests:wip-s3-cksum-type-algoCopy head branch name to clipboard