Public server registration should be disabled by default

[ashpool37]

The current default behaviour of this role is to configure the Murmur server to attempt to register itself with the public server registry, using the string password as the registration password. This is very insecure and could potentially lead to a lot of public server entries overtaken by spammers and other bad actors. Many people may not be willing to register their server publicly in the first place.

According to the documentation, setting the registerPassword value to be empty will disable the public server registration. I think this is what should be done by default.

[xshadow]

Hey ashpool37, thanks for the feedback. The value of registerPassword should be changed by the administrator when using this role. It seems that this is not clear. Would you like to create a pull request for either updating the Readme.MD accordingly or one for disabling the registration by default.

[ashpool37]

Yeah, I'll be following up with a few PRs concerning this and other issues with documentation, as well as security.