gapi: Move the World interface into resources

This was necessary to fix some "import cycle" errors I was having when
adding the World api to the resource Data struct.

I think this is a good hint that I need to start splitting up existing
packages into sub files, and cleaning up and inter-package problems too.

gapi/gapi.go

@@ -23,24 +23,10 @@ import (
 	"github.com/purpleidea/mgmt/resources"
 )
 
-// World is an interface to the rest of the different graph state. It allows
-// the GAPI to store state and exchange information throughout the cluster. It
-// is the interface each machine uses to communicate with the rest of the world.
-type World interface { // TODO: is there a better name for this interface?
-	ResExport([]resources.Res) error
-	// FIXME: should this method take a "filter" data struct instead of many args?
-	ResCollect(hostnameFilter, kindFilter []string) ([]resources.Res, error)
-
-	StrWatch(namespace string) chan error
-	StrGet(namespace string) (map[string]string, error)
-	StrSet(namespace, value string) error
-	StrDel(namespace string) error
-}
-
 // Data is the set of input values passed into the GAPI structs via Init.
 type Data struct {
 	Hostname string // uuid for the host, required for GAPI
-	World    World
+	World    resources.World
 	Noop     bool
 	NoWatch  bool
 	// NOTE: we can add more fields here if needed by GAPI endpoints