Configure which parameters to include in update

[oyvindeide]

As a user I would like to run multiple updates and very which parameters are updated, and which are just sampled, but not update, i.e. to vary the UPDATE flag between runs.

• The parameters are not necessarily in the same group, so setting the setting just on GEN_KW level is not a good solution
• Adding a config option to the prior file is an option, though a bit cumbersome
• Setting it in the GUI might be a good option, but being able to save it back to a config file would probably be nice then? Would require a different format as we dont have a way to write to the current format.