add getUserObjFromUsername util function,

update all backends to use userObj,
add user backend manager wrapper which calls all linked backends dealing with user data,
list backend handlers for each realm

config/template.config.json

@@ -30,10 +30,14 @@
 		}
 	},
 	"handlers": {
-		"pve": "pve",
-		"db": "localdb",
-		"auth": {
+		"instance": {
 			"pve": "pve"
+		},
+		"users": {
+			"pve": [
+				"localdb",
+				"pve"
+			]
 		}
 	},
 	"application": {