Notification setting for invites

[bmarty]

As a user that get invited I want to be able to switch of being notified about invitation so that I can miss them and be sad that I have no one to talk to.

TODO

Existing screen on EXA:

• Add a setting with a toggle in this notifications setting screen to enable / disable the notification for invites, in the Additional settings section which has to be unhidden (currently hidden, since it only contains call setting which is hidden - the call settings stay hidden), with the wording Invitations, and enabled by default (note that we read the value from the SDK, and it should be true by default, that's the default push rules).

For Reference: existing settings on EA

Notification settings	Other screen

DOD

When the new setting is disabled, new invitations does not trigger a notification, but are visible in the invites screen.
When the new setting is enable, new invitations trigger a notification, and are visible in the invites screen.

[bmarty]

Note that there is an Additional settings section which is commented out today: