[Nix] Add support for tunnelbroker build

Summary:
Only the dependencies being added to the nix develop shell

The related CMake changes were causing the gates to crash without the
docker fixes

Test Plan: nix develop and in a later diff, build tunnelbroker with cmake

Reviewers: varun, max

Reviewed By: varun, max

Subscribers: ashoat, tomek, adrian, atul, abosh

Differential Revision: https://phab.comm.dev/D4604