Add member "kind" - and refactor user "type" to "kind" for consistency (#16979)

* Rename UserType to UserKind

* Add MemberKind to tell API members from regular ones

* Remove user kind from invite user endpoint

---------

Co-authored-by: Mads Rasmussen <madsr@hey.com>

src/Umbraco.Web.Common/Security/BackOfficeUserManager.cs

@@ -299,7 +299,7 @@ public class BackOfficeUserManager : UmbracoUserManager<BackOfficeIdentityUser,
             _globalSettings.DefaultUILanguage,
             createModel.Name,
             createModel.Id,
-            createModel.Type);
+            createModel.Kind);
 
         IdentityResult created = await CreateAsync(identityUser);