stdout and file log level settings are inconsistent

[r4ntix]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
The current log level settings of the stdout and file are inconsistent:

• file: via the --log-level-setting parameter
• stdout: via the RUST_LOG env. if empty, this defaults to INFO

Describe the solution you'd like
Unified the log level configuration behavior: Use RUST_LOG env first, if empty, use the --log-level-setting parameter

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

[avantgardnerio]

+1 for removing --log-level-setting. From a devops perspective: III. Config - Store config in the environment