mimic: osd: set collection pool opts on collection create, pg load

mimic: osd: set collection pool opts on collection create, pg load

We need to tell the ObjectStore's Collections what the pool options are
for things like the bluestore compression mode and so on to take effect.

Apply these

- when we create new collections, due to a new pg or a split
- when we start up and open an existing collection

We already apply these changes when there is a pool change.

(This is a manual backport of 512d89af9ac0d19df44dedc67fe349022c656907).

Fixes: https://tracker.ceph.com/issues/40483
Signed-off-by: Sage Weil <sage@redhat.com>