[config, i18n] Create default translation mechanism for all supported languages. Mostly usefull in test where language are never initialised from .po files. This is a reapplication of changeset 1a423eaee782 backouted by b9ffecd0316a with an additional fix not to break i18nxxx commands

msgid ""
msgstr ""
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"
"Generated-By: pygettext.py 1.5\n"
"Plural-Forms: nplurals=2; plural=(n > 1);\n"