From https://phabricator.wikimedia.org/T121809
Implement SiteListGetter::getSiteList
https://github.com/addwiki/mediawiki-sitematrix-api/blob/master/src/Api/Service/SiteListGetter.php#L33
Use a MediawikiApi object to make a request 'action=sitematrix'
Parse the result and use it to make and return a SiteList object
From https://phabricator.wikimedia.org/T121809
Implement SiteListGetter::getSiteList
https://github.com/addwiki/mediawiki-sitematrix-api/blob/master/src/Api/Service/SiteListGetter.php#L33
Use a MediawikiApi object to make a request 'action=sitematrix'
Parse the result and use it to make and return a SiteList object