[lib] Introduce keyserver connection handler

Summary:
These components will handle the connections to keyservers. At this point they simply render a single Socket.

https://linear.app/comm/issue/ENG-5997/handlers-for-managing-keyserver-connections

Test Plan: Run the app on web and iOS and check if it is possible to use the socket by sending messages.

Reviewers: inka, kamil, atul, varun

Reviewed By: inka

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D10248