Investigate docker run errors in AppConfig BB

[minump]

Description

Running AppConfig in docker leads to error.
Running via docker leads to error : http://0.0.0.0:5000/app/configs/ok http://localhost:5000/app/configs/ok http://0.0.0.0:5000/app/configs/version
response :
{
"detail": "Expecting value: line 1 column 1 (char 0)",
"status": 501,
"title": "Not Implemented",
"type": "about:blank"
}
Running in python works fine.

Issue is reported in #1127 and #1074.

Need to investigate and fix the issue.

Acceptance Criteria

AppConfig builds and runs fine in docker