wikichecks - additional check & cleaned-up

* added param '' where lang key 'gwtoolset-permission-not-given' is used without a param
* added checkWikiVersion()
* moved self::checkMediaUploadSettings() to the bottom of pageIsReadyForThisUser
* removed @return {void} comments
* renamed verifyPHPVersion to checkPHPVersion

Change-Id: I5a69e638073393d7142bfce2d10bb14a5a2594e6