Make forwarder information part of the gateway uplink tokens

[adriansmares]

Summary

Reference https://github.com/packetbroker/router/issues/109

Changes

• The forwarder information (net ID, tenant ID and cluster ID) is now part of the signature of the encrypted gateway tokens.

Testing

Unit testing. On staging1 just checking that Packet Broker still works suffices.

Regressions

We did not have a release yet which uses the new optimized format, so adding the additional data won't break anything.

Notes for Reviewers

Are there situations during routing in which the forwarder information changes ? I am specifically afraid of a forwarder publishing their traffic, without a tenant ID let's say, and the router somewhere in its bowels adds this tenant ID while routing the message to the home network.

I am asking this because it would be problematic while receiving a routed downlink message since the forwarder additional data would be different (we used an empty string while sealing the token, but we are now trying to unseal it with another tenant ID being in there).

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• The steps/process to test this feature are clearly explained including testing for regressions.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.