Container should be created by a phpbb_create_default_container() function

There is quite some duplication of the following code:

$phpbb_container = phpbb_create_dumped_container_unless_debug(
array(
new phpbb_di_extension_config($phpbb_root_path . 'config.' . $phpEx),
new phpbb_di_extension_core($phpbb_root_path),
),
array(
new phpbb_di_pass_collection_pass(),
new phpbb_di_pass_kernel_pass(),
),
$phpbb_root_path,
$phpEx
);