fix: introduce system env var, remove debug mode (#4658)

* fix: introduce system env var

* docs

* docs

index.php

@@ -29,7 +29,7 @@ set_error_handler(function ($code, $message, $file, $line) use ($logger) {
         // Deprecation messages and other masked errors are typically ignored here
         return false;
     }
-    if (Debug::isEnabled()) {
+    if (Configuration::getConfig('system', 'env') === 'dev') {
         // This might be annoying, but it's for the greater good
         throw new \ErrorException($message, 0, $code, $file, $line);
     }