osd: Set default max active recovery and backfill limits for mClock

osd: Set default max active recovery and backfill limits for mClock

Client ops are sensitive to the recovery load and must be carefully
set for osds whose underlying device is HDD. Tests revealed that
recoveries with osd_max_backfills = 10 and osd_recovery_max_active_hdd = 5
were still aggressive and overwhelmed client ops. The built-in defaults
for mClock are now set to:

    1) osd_recovery_max_active_hdd = 3
    2) osd_recovery_max_active_ssd = 10
    3) osd_max_backfills = 3

The above may be modified if necessary by setting
osd_mclock_override_recovery_settings option.

Fixes: https://tracker.ceph.com/issues/58529
Signed-off-by: Sridhar Seshasayee <sseshasa@redhat.com>