[services] Tunnelbroker - Dev-mode environment variables in Docker

Summary:
To use the dev-mode inside the tunnelbroker we need to pass the COMM_SERVICES_DEV_MODE environment variable to the Docker container itself.

Linear task: ENG-1101

Test Plan: Run yarn run-tunnelbroker-service-dev-mode shows that the environment variable COMM_SERVICES_DEV_MODE is equal to 1.

Reviewers: karol-bisztyga, palys-swm

Reviewed By: karol-bisztyga, palys-swm

Subscribers: ashoat, palys-swm, Adrian, atul, karol-bisztyga, yayabosh

Differential Revision: https://phabricator.ashoat.com/D4131