Prep Plugin for release on WordPress.org (#23)

* Update translation text domain
* Escape everything that should be escaped.
* Add nonce checks where needed.
* Sanitize all inputs.
* Apply Code style changes across the codebase.
* Correct many deprecation notices.
* Optimize load order of many filters.
* Add Proper Build script
* Use emojii flags
* Fix i18n deprecation  notice for translating too early
* Put all scripts in footer and load async

inc/class-async-calls.php

@@ -38,13 +38,12 @@ class Async_Calls {
 	/**
 	 * Registers a new listener.
 	 *
+	 * @since 2.0.7
 	 * @param string   $id The id of the listener.
 	 * @param callable $callback A callback to be run.
 	 * @param mixed    ...$args Arguments to be passed to the callback.
 	 *
 	 * @return void
-	 *@since 2.0.7
-	 *
 	 */
 	public static function register_listener($id, $callback, ...$args): void {