LibJS: Consolidate error messages into ErrorTypes.h

Now, exceptions can be thrown with
interpreter.throw_exception<T>(ErrorType:TYPE, "format", "args",
"here").

Libraries/LibJS/Tests/template-literals.js

@@ -36,7 +36,7 @@ try {
         `${b}`;
     }, {
         error: ReferenceError,
-        message: "'b' not known"
+        message: "'b' is not defined",
     })
 
     console.log("PASS");