[ticket/11700] Fix another case of non-namespaced classnames

PHPBB3-11700
[ticket/11700] And some last comments with backslashes

PHPBB3-11700
[ticket/11700] Check for ALLOW_REMOTE_UPLOAD in acp output as expected

PHPBB3-11700
[ticket/11700] Fix leftover backslashes in comments

PHPBB3-11700
[ticket/11700] Correctly generate lang key from avatar driver class

PHPBB3-11700
[ticket/11700] Load avatar explanations correctly from namespaces

PHPBB3-11700
[ticket/11700] Correct service definitions with namespaces

PHPBB3-11700
[ticket/11700] namespacify phpbb_permissions class

PHPBB3-11700
[ticket/11700] Use underscores in avatar driver template file names

PHPBB3-11700
[ticket/11700] Correctly convert old acm type to namespaced class name

PHPBB3-11700
[ticket/11700] Correctly load extensions with nonprefixed namespaces

PHPBB3-11700
[ticket/11700] Add back accidently deleted file in cache dir

PHPBB3-11700
Merge remote-tracking branch 'github-phpbb/develop' into ticket/11700

* github-phpbb/develop:
  [ticket/11832] Correct paths in tests
  [ticket/11832] Correct ROOT_PATH variable
  [ticket/11832] get_url() from phpbb_template_asset should return web path
  [ticket/11832] Fix INCLUDE(JS/CSS)
  [ticket/11832] Fix constructions of phpbb_filesystem
  [ticket/11832] Fix smiley paths
  [ticket/11832] Create phpbb_symfony_request to handle initiating symfony_request
  [ticket/11832] Fix build_url and the S_LOGIN_ACTION
  [ticket/11832] Changing comments to say app.php rather than index.php
  [ticket/11832] We must instantiate the $phpbb_filesystem in common
  [ticket/11832] Fix the web path corrections
  [ticket/11832] More extensive testing
  [ticket/11832] Use dirname(__FILE__)
  [ticket/11832] Use $phpbb_filesystem instead of the container in append_sid
  Revert "[ticket/11832] Make $phpbb_container a global initiated by the framework"
  [ticket/11832] Make $phpbb_container a global initiated by the framework
  [ticket/11832] Fix log tests
  [ticket/11832] update_web_root_path helper and tests
  [ticket/11832] Inject dependencies for phpbb_get_web_root_path (also moving)

Conflicts:
	phpBB/common.php
	phpBB/config/services.yml
	phpBB/includes/bbcode.php
	phpBB/includes/functions.php
	phpBB/includes/functions_messenger.php
	phpBB/install/index.php
	phpBB/phpbb/filesystem.php
	phpBB/phpbb/template/twig/environment.php
	phpBB/phpbb/template/twig/node/includeasset.php
	phpBB/phpbb/template/twig/twig.php
	tests/controller/helper_url_test.php
	tests/dbal/migrator_test.php
	tests/extension/manager_test.php
	tests/extension/metadata_manager_test.php
	tests/filesystem/clean_path_test.php
	tests/mock/extension_manager.php
	tests/template/template_events_test.php
	tests/template/template_test_case.php
	tests/template/template_test_case_with_tree.php
	tests/test_framework/phpbb_functional_test_case.php
[ticket/11700] Fix unit tests after develop merge

PHPBB3-11700
[ticket/11700] Get functional tests running after develop merge

PHPBB3-11700
[ticket/11700] Namespace needed for mock object in web path test

PHPBB3-11700
[ticket/11700] Namespacif skipped filesystem instantiation in test

PHPBB3-11700
[ticket/11850] Fix $user->page on pages through the controller

PHPBB3-11850
[ticket/11700] Replace some leftover phpbb_filesystem uses

PHPBB3-11700
[ticket/11850] page_name contains controller request rather than query string

Fixing tests

PHPBB3-11850