Fix mismatches between `.env.example` and `.env`

[david1542]

Overview

We tend to modify our environment variables a lot. We do this by changing our .env locally, propagate the changes to our containers via docker-compose-common.yaml and then update .env.example.

However, when people pull the latest changes, their local .env remains the same since it is not committed go git (can contains secret stuff, like Slack bot token). This creates bugs and mismatches in the environments.

We need to find a better way to sync everyone to the latest environment variables setup.