[lib] Add Tunnelbroker message types for QR code auth

Summary:
Added a new peer-to-peer message type for QR code auth flow. All messages are going to be encrypted separately via AES-256.

Depends on D11292

Test Plan: TBD

Reviewers: kamil, michal

Reviewed By: kamil

Subscribers: ashoat, tomek

Differential Revision: https://phab.comm.dev/D11293