[web] update session creation code to handle versioning

Summary:
This code:

1. Updates contentInboundSessionCreator to decide whether to accept new or keep old session depending on sessionVersion
2. Updates contentOutboundSessionCreator to return the session version (right now by default we override session and bump counter).
3. Update Tunnelbroker message type to send sessionVersion along with init message

Depends on D11583

Test Plan:

1. Make sure session creation works
2. Outbound session creation cause bumping counter
3. Inbound session creation success or throw an appropriate error (tested all cases)

Reviewers: bartek, marcin, tomek

Reviewed By: marcin

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D11586