Feature
* feat(prometheus): add initial support for prometheus metrics
- use `litestar.contrib.prometheus` controller to expose a `/metrics`
endpoint for prometheus
- use `litestar.contrib.prometheus` middleware to collect
HTTP metrics for every request ([`737e782`](https://github.com/betaboon/aio-microservice/commit/737e78268e0206c517011ec3852ea6bf30caf280))