Returns Prometheus metrics.

Region is mandatory. Filter_tags (if any) should be written as string containing tag_name=tag_value

Results are estimated for one hour of use by default.

Example query: http://localhost:8000/metrics?aws_region=eu-west-3&filter_tag=Name=boatest&filter_tag=OtherTag=other-value&use_duration_hours=1.0&include_storage=true