Usecase-templates

Steps to add a new use case are:

1. Copy one of the use cases, modify the description, tags, etc.
2. Generate the rule template in the UI and paste that in the use case JSON.
3. Run generate_use_cases_metadata.py so that the use-cases.json file will be updated with new use case.
4. Commit the new use case json file and the modified use-cases.json