rgw/notifications: support metadata filter in COPY events

rgw/notifications: support metadata filter in COPY events

Fixes: https://tracker.ceph.com/issues/51261
Signed-off-by: Yuval Lifshitz <ylifshit@redhat.com> (cherry picked from commit
e7f30a1b278455567f1f1069f41c9a1c3ef335c2)

Conflicts:
        src/rgw/rgw_notify.cc
        src/rgw/rgw_notify.h
        src/test/rgw/bucket_notification/test_bn.py

Cherry-pick notes:
- handle differences due to renaming of rgw::sal::RGWObject to rgw::sal::Object
- handle differences due to move of test_ps_s3_metadata_on_master test from tests_ps.py to test_bn.py