Grafana: Add Tempest check runs graph
Grafana: Add Tempest check runs graph

This graph approximately answers the question "How many runs would
a third-party CI system be expected to handle for the integrated
gate?"

Change-Id: Iae74306ce3c922be3d82d61ca86e724f7e048dff

Tesora/tesora-project-config,dongwenjuan/project-config,openstack-infra/project-config,Tesora/tesora-project-config,dongwenjuan/project-config,openstack-infra/project-config