Replace stats.db with central datastore

[thomas-maschler]

Replace stats.db with central datastore (ie pg) to assure all microservices use the same version and to avoid having to sync all the time with stats.db from S3.
Create authenticated endpoints which allows to update database via microservice
POST /v1/glad-alerts/delete -d {"start_date":<yyyy-mm-dd>, "end_date":,<yyyy-mm-dd>}
POST /v1/glad-alerts/insert -f {"file":<new_data.csv>}