This patch adds threshold evaluator for Prometheus metrics.
Alarms are based on Prometheus query only. The library
python-observabilityclient is used for querying Prometheus.
Co-authored-by: Jaromír Wysoglad <jwysogla@redhat.com>
Depends-On: Ie7477e0b11479449f7f13c7a784737ac70059964
Change-Id: I72e124cca4398b78f7ed12e1db3f66bdbfcb196e