Implement alarms history cleanup via aodh-expirer

Added ability to create cron for aodh-expirer launch.
By default expirer will be launched on hourly basis.

Change-Id: I0a68cc4038e92932ca3fa97c6b6a137b9e0d168c
Related-Prod: https://mirantis.jira.com/browse/PROD-21307
3 files changed