[ticket/12575] Speed up load_class()

Load the services referenced in a service_collection only when
they are used to avoid to load some unsuded services.

PHPBB3-12575
[ticket/12575] Move service_collection_iterator to its own file

PHPBB3-12575
[ticket/12575] Fix the tests

PHPBB3-12575
[ticket/12575] Remove  inline assignments

PHPBB3-12575
[ticket/12575] Skip sniffer issue triggered by the solution of a php bug

https://bugs.php.net/bug.php?id=66834
https://bugs.php.net/bug.php?id=67067

PHPBB3-12575
[ticket/12575] Fix typos in comments

PHPBB3-12575
[ticket/12575] Fix 2 typos in comments

PHPBB3-12575
[ticket/12575] Usethe new header

PHPBB3-12575
[ticket/12575] Add missing property

PHPBB3-12575
[ticket/12575] Use strict comparison

PHPBB3-12575
[ticket/12706] Ignore additional styles

PHPBB3-12706
[ticket/12706] Ignore additional languages

PHPBB3-12706
[ticket/12706] Ignore additional rank images

PHPBB3-12706
Merge pull request #2589 from nickvergessen/ticket/12706

Ticket/12706 Add languages styles and rank images to git ignore

* nickvergessen/ticket/12706:
  [ticket/12706] Ignore additional rank images
  [ticket/12706] Ignore additional languages
  [ticket/12706] Ignore additional styles
Merge pull request #2483 from Nicofuma/ticket/12575

[ticket/12575] Use a proxy pattern in \phpbb\di\service_collection

* Nicofuma/ticket/12575:
  [ticket/12575] Use strict comparison
  [ticket/12575] Add missing property
  [ticket/12575] Usethe new header
  [ticket/12575] Fix 2 typos in comments
  [ticket/12575] Fix typos in comments
  [ticket/12575] Skip sniffer issue triggered by the solution of a php bug
  [ticket/12575] Remove  inline assignments
  [ticket/12575] Fix the tests
  [ticket/12575] Move service_collection_iterator to its own file
  [ticket/12575] Speed up load_class()