AppSettings, set update interval

[infeeeee]

• Part 4 of App settings again #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]

Really good management of the settings, I like it !