[feature/extension-manager] Add prefix to extension meta data / install classes

PHPBB3-10323

tests/extension/ext/bar/ext.php

@@ -0,0 +1,24 @@
+<?php
+
+class phpbb_ext_bar_ext extends phpbb_extension_base
+{
+	static public $state;
+
+	public function enable_step($old_state)
+	{
+		// run 4 steps, then quit
+		if ($old_state === 4)
+		{
+			return false;
+		}
+
+		if ($old_state === false)
+		{
+			$old_state = 0;
+		}
+
+		self::$state = ++$old_state;
+
+		return self::$state;
+	}
+}