feat: backend api with partial influxdb integration

[ymarcon]

• backend server: makes request to influxdb database for some sensors, or get csv files from s3 storage for others.
• use redis for caching fastapi responses and database query results and csv files content.
• resamples the data when time range is larger than a week (mean per hour), either using an appropriate query in influxdb or using pandas when data are coming from csv files.

Deployed in k8s: https://water-portal-dev.epfl.ch/