[ticket/12349] Update license header in several new files

PHPBB3-12349
[ticket/12349] Fix Sniffer for @license tag

PHPBB3-12349
Merge remote-tracking branch 'nickvergessen/ticket/12349' into develop-ascraeus

# By Joas Schilling
# Via Joas Schilling
* nickvergessen/ticket/12349:
  [ticket/12349] Fix Sniffer for @license tag
  [ticket/12349] Update license header in several new files
Merge branch 'develop-ascraeus' into develop

# By Joas Schilling
# Via Dhruv (1) and Joas Schilling (1)
* develop-ascraeus:
  [ticket/12349] Fix Sniffer for @license tag
  [ticket/12349] Update license header in several new files