add support for http mw in v2 version

[cbarik-infoblox]

Create a v2 version as specified in go.mod as github.com/infobloxopen/atlas-authz-middleware/v2

Since this version is specific to HTTP middleware without any support for grpc interceptors, for any consumer, who is supposed to use both grpc interceptor and http middleware, need to download both the versions (main and v2)

The middleware will validate the incoming HTTP requests by forwarding the endpoint and jwt token to the OPA engine running in the sidecar.

For the opa client, it expects a jwt token in the Authorization header, prefixed with Bearer and an optional X-Request-ID header.

Unauthorised requests will usually be rejected with a status of 401 Unauthorized