Add Locust support for authentication

[DuboisABB]

This issue is for a: (mark with an x)

- [ ] bug report -> please search issues before submitting
- [X] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)

Please modify locustfile.py to handle a web app where authentication is required (i.e. AZURE_USE_AUTHENTICATION=true and AZURE_ENABLE_UNAUTHENTICATED_ACCESS=false).

I attempted to use GitHub Copilot to add this feature but it doesn't work and I'm a bit over my head.