Update timeago to shorter representation

## What does this MR do?
Shortens representation of `Finished at` block in pipelines & builds

## What are the relevant issue numbers?
Closes #19752    
Part of https://gitlab.com/gitlab-org/gitlab-ce/issues/18920

## Screenshots (if relevant)
![Screen_Shot_2016-07-14_at_8.54.44_AM](/uploads/85000549c49165d4481422eac5eb0ca9/Screen_Shot_2016-07-14_at_8.54.44_AM.png)

See merge request !5225