Document how roles work

[KevM]

We are trying to adopt leukocyte but do not understand how roles are configured and how we can bind them to authorities.

FYI When we create an authority the user account that creates the authority is not affected by it. I did not see this documented anywhere. Is this expected behavior? All we tried was to add a cube and deny breaking, placing blocks. Testing worked only with different users. We would like to have the admin be affected by the authority as well.

[KevM]

FYI I'm happy to create a PR with better role docs once I understand them and how they work with your other project player-roles.