Refactor Config class

[willardgibbs]

1. Rename the settings in the configuration yaml-file, in the README.md and in the Config class (for readability and extensibility)
2. Group settings
3. Implement the classes describing the exporter setting groups
4. Implement automatic mapping of the file with settings in the configuration classes by the snakeyaml library
5. Use these classes in the remaining exporter classes