v2.4.6: Fix anonymous access + onboarding wizard

A fast bugfix release to fix #192 regarding anonymous access setting.

Actually this was all related to the new Nexus Onboarding Wizard which was introduced in nexus 3.17

The new nexus_onboarding_wizard settings can be set to true if you still want to see the wizard on first admin login. The wizard is now disabled by default as it was in previous version, and has it makes total sense when you run an automated deploy.

This was all fixed in #220. Thanks to @mjlshen for his contribution.