Arvados

refs #2836

- Updated the "Run this pipeline" button in the template display page

- Updated the "Run" button in the pipeline_templates in the recent templates view page

- Updated the integration test to work with the new UI

- Also, included in this story are the updates for "Show date-or-time instead of age" from #2836

This branch looks good. Thanks for an easy review. I just have one small comment and one suggestion, both about icons:

• The new button on the pipeline_templates#show page uses the fa-folder icon. While I understand the logic behind this, the relationship with the text "Run this pipeline" seems unclear. Perhaps fa-play would be more suitable? That's what we use on pipeline_templates#index.
• This second issue originated before your branch, but while we're changing it: it looks like most of our buttons have icons on the left, but the Run button on pipeline_templates#index has fa-play on the right. Do you think it'd look more consistent with the rest of the UI if we moved it to the left too?

The code is clean, so I'm happy for this to get merged, with or without patches if you feel strongly about the current icon situation. Thanks.