[Enhancement] Add ability to create an achievement table

[jmarquez90]

Background: Things like "find an XSS that causes a popup but doesn't pass the level, report a vulnerability in the platform, tell 5 of your classmates/colleagues about the platform and have them sign up, help someone pass a level, help someone understand an HTTP proxy etc." this should be on the landing page when people log in, when you assign points to a usr you can select an achievement and that user is put next to the achievement on the page.

Taken from UX Improvements for Admins #653. @ismisepaul