doc/cephfs: edit disaster-recovery-experts (5 of x)

doc/cephfs: edit disaster-recovery-experts (5 of x)

Put the procedure in the section called "Using an alternate metadata
pool for recovery" into an ordered list, so that it is in a proper
procedure format.

This commit is meant only to break the procedure into steps. The English
language in each of these steps could be improved, but that improvement
will be done after this formatting has been merged and backported.

Follows https://github.com/ceph/ceph/pull/61462.

https://tracker.ceph.com/issues/69557

Signed-off-by: Zac Dover <zac.dover@proton.me>