Refactor internal/server/user package structure

Co-authored-by: Roberto Abdelkader Martínez Pérez <robertomartinezp@gmail.com>

internal/server/user/routes_test.go

@@ -0,0 +1,14 @@
+package user
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/BBVA/kapow/internal/server/user/state"
+)
+
+func TestPackageHaveASingletonEmptyRouteList(t *testing.T) {
+	if !reflect.DeepEqual(Routes, state.New()) {
+		t.Error("Routes is not an empty safeRouteList")
+	}
+}