Use a configuration file for the local readout application

Description

While working, the local readout application cannot be configured at runtime, all configuration is statically defined in the source code. This must change.

Possible fixes

A YAML can be used to describe the desired configuration in a hierarchical way:

1. Port
2. Queue (with a specific destination MAC address)
3. Output module(s)

Any precise format should be described and eventually discussed here first.