Rules now adhere to the format defined by Prometheus.io.
This changes alert naming and each alert now includes a
a summary description to provide a quick one-liner.
In addition to reformatting some missing alerts for MDS and
cephadm have been added, and corresponding tests added.
The MIB has also been refactored, so it now passes standard
lint tests and a README included for devs to understand the
OID schema.
Fixes: https://tracker.ceph.com/issues/53111
Signed-off-by: Paul Cuzner <pcuzner@redhat.com>
