Turning in Move Mean/Median/Mode functions to a service assignment.

Turning in Move Mean/Median/Mode functions to a service assignment.
Thank you for your review!  Fixed https://github.com/HIROSN/mmm-website-using-angular/commit/3abc938a9c0d9b778b205aa55306f5e88b73ee10 (Travis: https://travis-ci.org/HIROSN/mmm-website-using-angular/builds/44156447).