[ticket/11974] Translate all timezones

PHPBB3-11974
[ticket/11974] Fix timezone names with underscores

PHPBB3-11974
Merge remote-tracking branch 'nickvergessen/ticket/11974' into develop

# By Joas Schilling
# Via Joas Schilling
* nickvergessen/ticket/11974:
  [ticket/11974] Fix timezone names with underscores
  [ticket/11974] Translate all timezones