[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

phpBB/config/default/container/services.yml

@@ -103,7 +103,7 @@ services:
             - @cache.driver
 
     filesystem:
-        class: phpbb\filesystem
+        class: phpbb\filesystem\filesystem
 
     file_downloader:
         class: phpbb\file_downloader
@@ -159,6 +159,7 @@ services:
     router:
         class: phpbb\routing\router
         arguments:
+            - @filesystem
             - @ext.manager
             - %core.root_path%
             - %core.php_ext%

phpBB/config/default/container/services_avatar.yml

@@ -58,6 +58,7 @@ services:
             - @config
             - %core.root_path%
             - %core.php_ext%
+            - @filesystem
             - @path_helper
             - @mimetype.guesser
             - @cache.driver

phpBB/config/default/container/services_console.yml

@@ -84,6 +84,7 @@ services:
             - @config
             - @cache
             - @log
+            - @filesystem
             - %core.root_path%
         tags:
             - { name: console.command }

phpBB/config/default/container/services_twig.yml

@@ -19,6 +19,8 @@ services:
 
     template.twig.loader:
         class: phpbb\template\twig\loader
+        arguments:
+            - @filesystem
 
     template.twig.extensions.collection:
         class: phpbb\di\service_collection