Add REST API for `Home Consumption Analytics` (home_load) domain

[GitGab19]

Child-issue of #7 specific for the Home Consumption Analytics (home_load) domain.

[markoceri]

Implementing the REST API for home loads requires implementing the full home loads stack (repository port, database adapters, dedicated configuration service functions, etc.).

The way edge mining produces (or retrieves) home load forecast data has been intentionally left incomplete in order to gain more insight into how home loads can be used.

The idea is to implement something very similar to the implementation for the energy forecasting domain, where ForecastInterval objects track the start and end dates of the forecasted energy consumption, the kWh values ​​of the forecasted energy, and finally a list of ForecastPowerPoints that track the instantaneous power forecasted in the interval.

Secondly, I plan to implement two specific adapters:

• One that retrieves data from an external system and populates the consumption history for a given home load, saving it to a local database. I believe this operation can be performed on demand directly from the frontend/API or CLI, or performed regularly directly from the optimization service. This second option is worth considering.
• The second uses historical data relating to the specific home load to estimate future consumption.

Further details on the basic functionality of the home loads domain will be discussed in issue #8.

In conclusion, the implementation of the features that solve this problem are subordinated to the definition of the elements of the home load domain.

[GitGab19]

Blocked by #8