Fill time.settings.monthnames with localized strings by MW's $wgLanguageCode

$wgLanguageCode is the wiki's language, so the month names are not in the user's language yet.
Using messages for achieving this.

Change-Id: I8b1d0dffd43b51a934580daad679e82133962fbb
Merge "Fill time.settings.monthnames with localized strings by MW's $wgLanguageCode"