Minor changes in the pipeline to handle gracedb-playground

Very minimal changes to make bayeswave_pipe able to digest a "--gdb-playground" option which will result working with the playground GraceDB server instead of the production server.

I did one test run with and one without the new option and it seems to work. And because the changes are really minimal, it shouldn't interfere with anything.

Making the merge is not very pressing, because I can use my own version for testing for ER13/O3 online running, but it would be nice to have this functionality for the future.