Shorten configuration file by removing all arguments where default values are used

[anders-kiaer]

In order to show that the configuration file can actually be quite short (if default values are okey), it would be nice to remove all options where we are only using default values from the configuration file.

Another use case is however "copy/paste" an initial configuration where you see easily which arguments are available. However this use case is hopefully solved with webviz-config-editor going forward.