Functions (_g_get_time_charset and _g_get_ctype_charset) to get LC_TIME and LC_CTYPE charset
by using nl_langinfo with _NL_TIME_CODESET and CODESET).
Another functions (_g_locale_time_to_utf8 and _g_locale_ctype_to_utf8) which uses thel and format
the input string accordingly.
Add new test cases with mixing UTF8 and non UTF8 LC_TIME along with UTF8
and non UTF8 LC_MESSAGES.
Closed#2055
Signed-off-by: Frederic Martinsons <frederic.martinsons@sigfox.com>
