MQTT Broker - HAPI cannot connect after Docker deployment with error `Not authorized`

[rapcmia]

Describe the bug

This issue was found while checking a fresh Docker deployment of hummingbot-api. After running make setup, and make deploy, the API started and normal REST calls worked, but it could not connect to the MQTT broker. The API kept trying to reconnect, but the broker rejected the connection.

• The broker could not read the file it needs to set up the API login, so the expected account was never created. This makes the broker reject the API even when the configured username and password are correct.
• The same result occurred in a second, freshly pulled hummingbot-api workspace using the same Docker deployment flow, so it does not appear to be caused by old local files or an old image.
• The logs include a Permission denied message for the broker setup file, which gives developers a clear starting point for investigation.

Steps to reproduce bug

1. In a fresh HAPI, run make setup (or if you use existing use make reset;make setup)
2. Confirm that the HAPI starts and normal REST calls are available.
3. Check the HAPI logs and confirm that its MQTT connection is repeatedly rejected and retried.
4. Check the broker logs and confirm that it could not read its login setup file (Permission denied).
5. Repeat the same Docker deployment in another fresh workspace and confirm that the MQTT connection is still rejected.

[david-hummingbot]

Fixed with #225