XWIKI-11488 All time activity data ends in 2013

* display the last 5 years to add consistency with the chart Stats.AllTimeActivity
XWIKI-11488 All time activity data ends in 2013

* the activity chart should display the last 5 years (2 years in the future will bring no information for the user since they will be empty)
Merge pull request #362 from oanat/patch-4

XWIKI-11488 All time activity data ends in 2013