[lib] implementing handling peer-to-peer messages

Summary:
Making this shared code on the web and native using methods implemented in previous diffs.

This will simplify working with peer-to-peer messages in the future.

Depends on D11119

Test Plan:
Native: just a refactor
Web: tested in next diff

Reviewers: marcin, varun, tomek, michal

Reviewed By: tomek

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D11120