Bug 925278 - Make firefox/channel page localizable
* enclose strings in l10n calls + add l10n comments
* remove chevrons that are for decoration and cause l10n problems and generate them via CSS (gecko will revert them automatically in rtl)

Bug 925278 : use bedrock channel page instead of php one

* Add a bedrock redirect for firefox/channel
* include first locales ready: de, he
* mark strings in menu, page title, page description as localizable