Metric update

[DanteNiewenhuis]

Summary

Changed the type of multiple metrics.

Implementation Notes ⚒️

• All metrics that measure time, such as cpu_time_active or uptime are now in milliseconds.
• All timestamps are converted to milliseconds as well.

External Dependencies 🍀

N/A

Breaking API Changes ⚠️

1. Experiments might expect datetime object when loading into something like pandas. This will not work with the new int type, but should be easy to update
2. Some metrics will result in values 1000 * higher because they are converted from seconds to milliseconds.

Simply specify none (N/A) if not applicable.