wip try better code organisation with ajax

plugins/wp_model_plugin/js/ajax.js

@@ -0,0 +1,29 @@
+function ajax_post(data, action, callback_response, callback_error) {
+	const data = new FormData();
+	data.append('action', action);
+	data.append('_ajax_nonce', php_data.nonce);
+	data.append('data', data);
+
+	fetch(php_data.ajax_url, {
+		method: 'POST',
+		credentials: 'same-origin',
+		body: data
+	})
+	.then((response) => response.json())
+	.then((data) => {
+		if (callback_response)
+			callback_response(data);
+		else {
+			console.log("data: ");
+			console.log(data);
+		}
+	})
+	.catch((error) => {
+		if (callback_error)
+			callback_error(error);
+		else {
+			console.log("error: ");
+			console.log(error);
+		}
+	});
+};