AppSettings, set update interval

Part 4 of #90 separation
New class next to Warehouses and Entities: Settings
Currently only one type of settings available: AppSettings, and there two option:
- Change the update interval
- Change the retry interval after connection to broker is lost. Useful to increment for laptops, where losing connection is expected.
SettingsManager is a Singleton, where Settings' configs stored.
You can get the settings from the Settings Classes itself, it's not necessary to call SettingsManager directly, this is the basic pattern how config values can be returned:
```
from IoTuring.Settings.Deployments.AppSettings.AppSettings import AppSettings, CONFIG_KEY_UPDATE_INTERVAL
```

self.updateTimeout = int(AppSettings.GetFromSettingsConfigurations(CONFIG_KEY_UPDATE_INTERVAL))



Closes #5

richibrics / IoTuring