controller

It would be good to add proper building instructions for Windows (installing packages/libs etc.) in BUILDING.md.
Preferably using msys2. It is already used with CI. It works good and allows installing multiple tools and libraries for windows.

When I use APISIX, the business itself needs relatively complex routing rules, so I use Annotation of Ingress

But I didn't find the Apisix Ingress Annotation document,

Like this link nginx-ingress-annotation-document

Found this link [apisix-ingress-annotation-document](https://apisix.apache.org/docs/

It would be good to add a mention about healthEndpoint to documentation as it is super useful when using urlFrom.ingressRef

At least I could not easily find the complete list of supported values. Luckily found a mention in https://github.com/stakater/IngressMonitorController/blob/master/docs/migration-guide.md

It is not the first doc to read as I started using the operator from the start.