[News Feed] Implement the Notification setting

[jrainville]

This is the setting telling if the user wants to receive News or not.
By default, this setting should be set to true, ie active.

When the user turns off the setting, then we need to turn off the RSS listening and also not fetch anymore when coming back from offline.

[jrainville]

@seanstrom I saw that you had a branch for the News notification setting. This seems to be this issue here. Can I assign you?

[seanstrom]

@jrainville yup yup sounds good! thanks for making the issue 🙌