Use injection in and for LimboCache, migrate some legacy settings, remove setGroup from Utils

- New injector method allows to retrieve services if they've already been instantiated -> useful for onDisable() which might be run after aborted initialization
- Deprecate various methods that need to be removed

src/main/java/fr/xephi/authme/process/ProcessService.java

@@ -2,6 +2,7 @@ package fr.xephi.authme.process;
 
 import fr.xephi.authme.output.MessageKey;
 import fr.xephi.authme.output.Messages;
+import fr.xephi.authme.permission.AuthGroupType;
 import fr.xephi.authme.permission.PermissionNode;
 import fr.xephi.authme.permission.PermissionsManager;
 import fr.xephi.authme.settings.NewSetting;
@@ -102,4 +103,8 @@ public class ProcessService {
         return permissionsManager.hasPermission(player, node);
     }
 
+    public boolean setGroup(Player player, AuthGroupType group) {
+        return permissionsManager.setGroup(player, group);
+    }
+
 }