mgr/telemetry: default to reports every 24h; lower minimum

mgr/telemetry: default to reports every 24h; lower minimum

Allow more frequent telemetry reports.

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 712987d53337e39ad871ee7abb38c2e2755fc75d)

Conflicts:
	src/pybind/mgr/telemetry/module.py
          Past commit in master had introduced field types and a
          'minimum' value for the interval. We concluded that the field
          types commit does not affect the telemetry module in a
          significant way to force us to backport it, and the minimum
          value commit is introduced for the benefit of the dashboard
          (which, in luminous, does not have control over telemetry)