resources: Add JavaScript transpiling solution

Add a new pipe called TranspileJS which uses the Babel cli. This makes it possible for users to write ES6 JavaScript code and transpile it to ES5 during website generation so that the code still works with older browser versions.

Fixes #5764

tpl/resources/init.go

@@ -60,6 +60,11 @@ func init() {
 			[][2]string{},
 		)
 
+		ns.AddMethodMapping(ctx.TranspileJS,
+			[]string{"transpileJS"},
+			[][2]string{},
+		)
+
 		return ns
 
 	}