Add data validation, pipeline and scheduler.

- Perform data validation on each measurement insert
- Update metadata accodingly to validation
- Add scheduler and pipeline
- Add batch mislabelled sensors check
- Add batch median calculation
- Paginate through measurements while performing batch job
- Label spikes in median
- Label status of a sensor (broken, ok, not enough data)
Remove kafka.
Merge pull request #3 from MastodonC/data-quality-2

Data quality, pipeline and scheduler.