Add Org user revoke feature

This PR adds a the new v2022.8.x revoke feature which allows an
organization owner or admin to revoke access for one or more users.

This PR also fixes several permissions and policy checks which were faulty.

- Modified some functions to use DB Count features instead of iter/count aftwards.
- Rearanged some if statements (faster matching or just one if instead of nested if's)
- Added and fixed several policy checks where needed
- Some small updates on some response models
- Made some functions require an enum instead of an i32

src/api/admin.rs

@@ -418,15 +418,26 @@ async fn update_user_org_type(data: Json<UserOrgTypeData>, _token: AdminToken, c
     };
 
     if user_to_edit.atype == UserOrgType::Owner && new_type != UserOrgType::Owner {
-        // Removing owner permmission, check that there are at least another owner
-        let num_owners =
-            UserOrganization::find_by_org_and_type(&data.org_uuid, UserOrgType::Owner as i32, &conn).await.len();
-
-        if num_owners <= 1 {
+        // Removing owner permmission, check that there is at least one other confirmed owner
+        if UserOrganization::count_confirmed_by_org_and_type(&data.org_uuid, UserOrgType::Owner, &conn).await <= 1 {
             err!("Can't change the type of the last owner")
         }
     }
 
+    // This check is also done at api::organizations::{accept_invite(), _confirm_invite, _activate_user(), edit_user()}, update_user_org_type
+    // It returns different error messages per function.
+    if new_type < UserOrgType::Admin {
+        match OrgPolicy::is_user_allowed(&user_to_edit.user_uuid, &user_to_edit.org_uuid, true, &conn).await {
+            Ok(_) => {}
+            Err(OrgPolicyErr::TwoFactorMissing) => {
+                err!("You cannot modify this user to this type because it has no two-step login method activated");
+            }
+            Err(OrgPolicyErr::SingleOrgEnforced) => {
+                err!("You cannot modify this user to this type because it is a member of an organization which forbids it");
+            }
+        }
+    }
+
     user_to_edit.atype = new_type;
     user_to_edit.save(&conn).await
 }