Feature Change - Add Metric Type Alerts in Terraform

In the work done as part of #150 (closed), Log alerts were added to Terraform. There is a need to add Metric alerts as well, since there are many metrics auto-collected in Azure Monitor which do not show up in the logs (example - osdu-airflow-dag related metrics)

Acceptance Criteria

• Add metric type alert in monitoring resources
• Provide sample data in terraform.tfvars file
• Update Documentation
• Deploy sample alert in ingestion environment

To set up pipeline support for monitoring resources, a separate issue will be created.