Improve configuration of the knowledge engine.

[bnouwt]

Currently, configuration is done via various environment variables and a startup parameters. Maybe improve upon this while keeping the following features in mind:

• easy use within docker containers (i.e. support environment variables)
• support hierarchical configuration keys
• support default values

A list of config libraries can be found here: https://www.reddit.com/r/java/comments/vc4llb/benchmark_of_java_configuration_libraries/

[bnouwt]

Here is another list: https://github.com/akullpp/awesome-java?tab=readme-ov-file#configuration

[bnouwt]

There is also a configuration standard: https://microprofile.io/specifications/microprofile-config/