mon: OSDMonitor: add 'osd pool get-quota' command

Enables us to obtain current quotas for a given pool.

Fixes: #8523

Signed-off-by: Joao Eduardo Luis <joao.luis@inktank.com>
(cherry picked from commit 714a9bb5a058b2553f3be3e4cfb7e7f30150e75a)
qa/workunits/cephtool/test.sh: fix get erasure_code_profile test

Manual backport of 4d6899c7560e990650959b442980a7249f0ba4c1

Signed-off-by: Sage Weil <sage@redhat.com>
  Fix EINVAL err when use "ceph tell osd.* bench"

  Signed-off-by: huangjun <hjwsm1989@gmail.com>
(cherry picked from commit 7dc93a9651f602d9c46311524fc6b54c2f1ac595)