Remove unneeded namecoin and snowflake definitions in rbm.conf
After discussing a similar issue in #32435 (moved), we noticed that we have some lines in rbm.conf that explicitly disable namecoin and snowflake but are not really needed.
When I want to see if a feature is enabled/disable I usually look at all the lines setting the option, so I find it better to have less lines to look at. So I think it's better if we remove the definitions that are not needed.
I think an exception to that rule would be if we wanted to add a comment explaining why we a feature is disabled (however it seems we don't have this case yet).
An other exception is the line setting var/multi_lingual to 0. In this case, we don't set it anywhere else, so I think it's useful to keep it to remind us that the option exists and can be changed.
So if everybody agrees with that rule, I think we should remove the snowflake: 0 and namecoin: 0 lines from rbm.conf.