improve configuration process
Sketch of the new configuration process:
Propertiesto store and read the configuration parameters.
- read external configuration properties file (either local path or via command line argument).
- provide a default configuration as resource within the executable jar.
- if there is no external configuration file present, write out the default values.
- re-read properties when file changes; only between module runs (this is after the implementation of the scheduler, legacy/trac#19018 (moved))
- use enum as keys
Questions to decide:
- property format: XML or plain properties (the latter might be more readable)
- default value settings