Move user_is_protected() and user_is_registered() into user.h/.c

src/user.h

@@ -200,6 +200,17 @@ extern int user_is_connecting(struct user* user);
  */
 extern int user_is_disconnecting(struct user* user);
 
+/**
+ * Returns 1 if a user is protected, which includes users
+ * having any form of elevated privileges.
+ */
+extern int user_is_protected(struct user* user);
+
+/**
+ * Returns 1 if a user is registered, with or without privileges.
+ */
+extern int user_is_registered(struct user* user);
+
 /**
  * User supports the protocol extension as given in fourcc.
  * This is usually set while the user is connecting, but can