Add four levels for Contrail processes and API alerts

info - per-service alerts with full set of labels
warning - alerts for more than 30% unavailable services
critical - alerts for more than 60% unavailable services
down - alerts for all unavailable services

Thresholds are configurable via params:
 * contrail_failed_warning_threshold_percent
 * contrail_failed_critical_threshold_percent

Change-Id: Ia39cab07e771f7e1ac835f24440ea1981dd048c9
2 files changed