mon/HealthMonitor: raise AUTH_INSECURE_GLOBAL_ID_RENEWAL[_ALLOWED]

mon/HealthMonitor: raise AUTH_INSECURE_GLOBAL_ID_RENEWAL[_ALLOWED]

Two new alerts:

- AUTH_INSECURE_GLOBAL_ID_RENEWAL_ALLOWED if we are allowing clients to reclaim
global_ids in an insecure manner (for backwards compatibility until
clients are upgraded)

- AUTH_INSECURE_GLBOAL_ID_RENEWAL if there are currently clients connected that
do not know how to securely renew their global_id, as exposed by
auth_expose_insecure_global_id_reclaim=true.  The client auth names and IPs
are listed the alert details (up to a limit, at least).

The docs recommend operators mute these alerts instead of silencing, but
we still include option that allow the alerts to be disabled entirely.

Signed-off-by: Sage Weil <sage@newdream.net>
(cherry picked from commit 18b343b06e5dd904af425dc99e2c848e12f3b552)