Help:Extension:Translate/Statistics and reporting

Both for the translator, to know how to find things to do, and the project coordinators, to monitor what's going on; and to make visualizations of the wiki community/work for the outside.

Things to cover:
 * Special:LanguageStats
 * Special:TranslationStats
 * Special:MessageGroupStats
 * Special:SupportedLanguages
 * cli stats scripts
 * Other useful extensions like contributionscores, semantic (maps)
 * logs
 * recent changes filtering
 * recent changes feeds