Sub configuration as blocks in configuration files

[PhilippWendler]

Sometimes, a configuration option refers to one or more further configuration options, e.g.,

sequential-analyses.configs = config1.properties, config2.properties

Sometimes, the exact config1.properties etc. does not fit, but needs some slight adjustments, i.e., some configuration values overwritten. This is only possible to handle by creating an extra file with #include config1.properties and the overwriting definitions.

As alternative, sub configurations like in the case above could be defined directly inside the main config file, like in this example:

sequential-analyses.configs = @config1, config2.properties

config1 {
  #include config1.properties
  overwritten-option = ...
}

This would be possible if the option sequential-analyses.configs is not defined as a list of file names, but as a list of Configuration instances, which could be created and injected directly.