[ticket/13697] Moving filesystem related functions to filesystem service

* Moving filesystem service to \phpbb\filesystem namespace
 * Wraping Symfony's Filesystem component
 * Moving filesystem related functions from includes/functions.php
   into \phpbb\filesystem\filesystem
   Functions moved (and deprecated):
     - phpbb_chmod
     - phpbb_is_writable
     - phpbb_is_absolute
     - phpbb_own_realpath
     - phpbb_realpath
 * Adding interface for filesystem service

PHPBB3-13697

tests/test_framework/phpbb_database_test_case.php

@@ -58,7 +58,7 @@ abstract class phpbb_database_test_case extends PHPUnit_Extensions_Database_Test
 
 		$setup_extensions = static::setup_extensions();
 
-		$finder = new \phpbb\finder(new \phpbb\filesystem(), $phpbb_root_path, null, $phpEx);
+		$finder = new \phpbb\finder(new \phpbb\filesystem\filesystem(), $phpbb_root_path, null, $phpEx);
 		$finder->core_path('phpbb/db/migration/data/');
 		if (!empty($setup_extensions))
 		{

tests/test_framework/phpbb_database_test_connection_manager.php

@@ -365,7 +365,7 @@ class phpbb_database_test_connection_manager
 		{
 			global $phpbb_root_path, $phpEx, $table_prefix;
 
-			$finder = new \phpbb\finder(new \phpbb\filesystem(), $phpbb_root_path, null, $phpEx);
+			$finder = new \phpbb\finder(new \phpbb\filesystem\filesystem(), $phpbb_root_path, null, $phpEx);
 			$classes = $finder->core_path('phpbb/db/migration/data/')
 				->get_classes();
 

tests/test_framework/phpbb_functional_test_case.php

@@ -254,7 +254,7 @@ class phpbb_functional_test_case extends phpbb_test_case
 			$container,
 			$db,
 			$config,
-			new phpbb\filesystem(),
+			new phpbb\filesystem\filesystem(),
 			$user,
 			self::$config['table_prefix'] . 'ext',
 			dirname(__FILE__) . '/',

tests/test_framework/phpbb_session_test_case.php

@@ -34,7 +34,7 @@ abstract class phpbb_session_test_case extends phpbb_database_test_case
 		$symfony_request = new \phpbb\symfony_request(
 			new phpbb_mock_request()
 		);
-		$phpbb_filesystem = new \phpbb\filesystem();
+		$phpbb_filesystem = new \phpbb\filesystem\filesystem();
 		$phpbb_path_helper = new \phpbb\path_helper(
 			$symfony_request,
 			$phpbb_filesystem,