RGW: remove custom copy constructor for RGWObjectCtx and enforce no copy/move

RGW: remove custom copy constructor for RGWObjectCtx and enforce no copy/move

The custom copy constructor allowed RGWObjectCtx to be copied without
locking the source, enabling concurrent modifications of objs_state
during std::_Rb_tree::_M_copy(). This could corrupt the map and cause
crashes during copy or destruction. Since RGWObjectCtx is not meant to
be copied or moved, remove the custom copy constructor and rely on the
type's natural non-copyable semantics, with static assertions enforcing
the contract.

Related to: https://tracker.ceph.com/issues/62063
Signed-off-by: Oguzhan Ozmen <oozmen@bloomberg.net>