osd_types: add recovery counts to object_sum_stats_t

Signed-off-by: Sage Weil <sage@inktank.com>
osd: track recovery ops in stats

Signed-off-by: Sage Weil <sage@inktank.com>
mon/PGMap: include timestamp

Signed-off-by: Sage Weil <sage@inktank.com>
mon/PGMap: report recovery rates

Signed-off-by: Sage Weil <sage@inktank.com>
mon/PGMap: report IO rates

This does not appear to be very accurate; probably the stat values we're
displaying are not being calculated correctly.

Signed-off-by: Sage Weil <sage@inktank.com>
mon: smooth pg stat rates over last N pgmaps

This smooths the recovery and throughput stats over the last N pgmaps,
defaulting to 2.

Signed-off-by: Sage Weil <sage@inktank.com>