[codecarbon] integration (#15)
* add codecarbon
* switch to offline
* rework to also restart the tracker at each checkpoint save to ensure as little as possible data is lost
* adjust API to match https://github.com/bigscience-workshop/codecarbon/pull/1
* fix logging
* new implementation based on https://github.com/mlco2/codecarbon/pull/236
* add test
* update requirements
