DAR-319: Added more information for chat logs

During investigation of the bug descriped in the [DAR-319](https://wikia-inc.atlassian.net/browse/DAR-319) we found out the bug doesn't exist there anymore but we can improve the log information passed from chat. I made changes in chat code so we display now XFF and user agent data in Special:Log and Special:CheckUser. I also did small clean-up in PHP code.