osd: osd_types: add pool quota related fields
encode, decode, and dump new fields
OSD: reject writes to full pools based on FLAG_FULL_POOL

Signed-off-by: Samuel Just <sam.just@inktank.com>
Revert "OSD: reject writes to full pools based on FLAG_FULL_POOL"

This reverts commit b8fb719df9320c33a9c3508588173531e101a7a5.
ReplicatedPG: check for full if delta_stats.num_bytes > 0

Signed-off-by: Samuel Just <sam.just@inktank.com>