Patch request: Disable "Linked Devices" feature

[aaronshenhao]

The patch should:

1. Remove the "Linked Devices" option.
2. Either prevent messages being sent to any linked devices (not sure how it works behind the scenes), or logging out of all devices periodically (e.g. when the app loads) to ensure that there are no linked devices.

The reason for doing this is due to security and privacy concerns. I am aware of an ongoing abusive relationship, in which the abuser uses this feature to constantly spy on their victim, who is technologically illiterate.