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/domain-mapping/class-helper.php

@@ -230,7 +230,7 @@ class Helper {
 			// Log the error message.
 			wu_log_add(
 				'domain-ssl-checks',
-				sprintf(__('Certificate Invalid: %s', 'wp-ultimo'), $e->getMessage()),
+				sprintf(__('Certificate Invalid: %s', 'wp-multisite-waas'), $e->getMessage()),
 				LogLevel::ERROR
 			);
 		}