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

views/base/edit/widget-list-table.php

@@ -28,7 +28,7 @@
 	<div class="wu-p-12 wu-h-12 wu--mt-1 wu--mx-3 wu--mb-3 wu-bg-gray-100 wu-text-gray-500 wu-text-xs wu-text-center">
 	<span class="dashicons dashicons-warning wu-h-8 wu-w-8 wu-mx-auto wu-text-center wu-text-4xl wu-block"></span>
 	<span class="wu-block wu-text-sm wu-mt-2">
-		<?php printf(__('%s will show up here once this item is saved.', 'wp-ultimo'), $title); ?>
+		<?php printf(esc_html__('%s will show up here once this item is saved.', 'wp-multisite-waas'), esc_html($title)); ?>
 	</span>
 	</div>