This is a major refactor moving from go-swagger to oapi-codegen.

This is due to go-swagger not supporting (and not going to support)
openapi 3 (see https://github.com/go-swagger/go-swagger/issues/1122

)

This also changed a couple things:
* Swagger 2.0 -> Openapi 3.0
* Making more settings configurable through envvars
  (ex. build_id_prefix)
* Added an option to run the server out of a k8s cluster (will use
  your local kubeconfig) -> out_of_k8s_run

It's a backwards compatible refactor, so no external functional
changes should have happened.

Bug: #338478
Signed-off-by: David Caro <me@dcaro.es>