Support "public" services in the vert.x gateway impl

I recently implemented "public" services which are Services that can be invoked directly without needing a Service Contract (or an Application for that matter).

The way this works is that a request can be sent to the Gateway without including an API key. When this happens the service coordinates must be included on the ServiceRequest prior to executing it in the engine.

I believe this means that the gateway must also be updated to support the standard apiman gateway format of:

http://host:port/gateway/{orgId}/{serviceId}/{version}/

The service coordinates must be extracted from that path and included on the Service Request. If no service coordinates can be determined (e.g. not enough path segments) then the gateway should reject the request.