Option to change worldBlacklist into a whitelist

[simondumalski]

Is your feature request related to a problem? Please describe.
I only want shops to be enabled in one world. Every time I create a new world, I have to go to the config and add the new world to the blacklist.

Describe the solution you'd like
I would like a config option to toggle the worldBlacklist into a whitelist, meaning that worlds listed will be the only worlds where shops can be created

Describe alternatives you've considered
No alternative available to my knowledge

Additional context

# Add the names of worlds that you do not want shops to be able to be created in here #
worldBlacklist:
- 'resource_world'
- 'spawn'

Add an option to the config area called "blacklist-is-whitelist" or something similar, and make it just a boolean.
If true, the worldBlacklist is now a whitelist, false (default), it is a blacklist