Create new websockets per subscription

As it stands now the subscriptions in combination with the websocket id's allow to track communication anonymously _(the server host can identify which device is communicating with which other device)_. It would be a lot harder to track the relation if the subscriptions are sent through a set of connections _(the timing would still be indicative of same connections)_. Not sure how the performance would be like on react-native with several sockets open and it would increase the memory load on the notification serve.r

Start by reviewing the notification server and its React Native/Expo client, focusing on how subscriptions are assigned to websocket connections and ids. The issue provides no file or test entry point; completion would require agreeing on the connection strategy and evaluating its privacy, performance, and memory effects.

Written by the indexing model from the issue text.