Add Total Duration to CI/CD Analytics Page

What does this MR do?

This MR adds the summed-up duration of all pipelines of a project on the CI/CD analytics page.

It also moves the formatPipelineDuration method of the time_ago component (see highlighted screenshot of it below) into a util file. Currently, that method only works for durations < 24 hours because the implementation used the native Date method. I replaced the implementation with arithmetic operators (modulo and division), in order for it to work in projects with many and/or long-running pipelines, such as the GitLab project.

Why "total duration"? I find it an interesting stat, however an average pipeline duration per day, week, or month might be more helpful if a user wants to reduce the pipeline durations.

Screenshots

time_ago component

Highlighted in the screenshot with a magenta border:

CI/CD Analytics Page

Before	After

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team