Swagger UI (OpenAPI) is missing statistics endpoints

[hendrikebbers]

We provide several statistics endpoints that are used to create https://dash.adoptium.net. An example is https://api.adoptium.net/v3/stats/downloads/total. Those endpoints can not be found in our swagger frontend at https://api.adoptium.net/q/swagger-ui/.

We should check what endpoints are missing at the OpenApi definition and add them.

[gdams]

I think the idea was to intentionally not document them so we can make breaking changes but we could discuss documenting them going forwards