WIP on user achievements

+ Add MCI codes for points/count
+ Add docs for MCI codes
+ Record in stats, stat log, etc.
* Do not trigger more than once
* Code cleanup & organization, add classes, etc.
* Tweaks to DB table

core/stat_log.js

@@ -359,6 +359,7 @@ class StatLog {
             systemEvents.UserUpload, systemEvents.UserDownload,
             systemEvents.UserPostMessage, systemEvents.UserSendMail,
             systemEvents.UserRunDoor, systemEvents.UserSendNodeMsg,
+            systemEvents.UserAchievementEarned,
         ];
 
         Events.addListenerMultipleEvents(interestedEvents, (eventName, event) => {