Investigate seasonality in recorded timeseries

### Why
We assume that within the 3 months worth of recorded data there will be shifts in consumption behavior of a costumer.
We want to detect such shifts and extract the corresponding consumption periods to perform additional analysis over each period type.

### What
Attempt 3 approaches:
- [ ] Seasonality analysis (CT)
- concatenate all time series for each customer
- perform decomposition time series
- extract seasonal windows
- investigate seasonal component filtering options
- [ ] Investigate time series periodicity [MT]
- start from ideas [described here](https://stats.stackexchange.com/questions/1207/period-detection-of-a-generic-time-series)
- [ ] Investigate periodicity by clustering (AS)