Load Testing for VDR Proxy

[cvarjao]

• Implemented using https://locust.io/
  • can we re-use the work https://github.com/openwallet-foundation/owl-akrida
• test/verify HA setup

[bryce-mcmath]

@jeznorth Since I volunteered for the load testing work and I will be away for a couple weeks, can probably take this out of the current sprint and I will tackle it at the same time I tackle the load testing for the Credo mediator when I get back.