Column chart type

We need to implement a wrapper for our bar chart using echarts in gitlab-ui.

@ameliabauerly already had some designs for this that I think are almost done, so we can probably leverage that.

It would be bonus if we could replace the commit chart in https://gitlab.com/gitlab-org/gitlab-ce/pipelines/charts with this echarts implementation (if that's okay with @jhampton's team) but not required for this issue to be considered complete.