new: [ACL] added canEditUser() function

- simple comparison between two users
- checks role + org based permission

src/Controller/Component/ACLComponent.php

@@ -277,9 +277,29 @@ class ACLComponent extends Component
         $this->user = $user;
     }
 
-    public function getUser(): User
+    public function getUser(): ?User
     {
-        return $this->user;
+        if (!empty($this->user)) {
+            return $this->user;
+        }
+        return null;
+    }
+
+    public function canEditUser(User $currentUser, User $user): bool
+    {
+        if (empty($user) || empty($currentUser)) {
+            return false;
+        }
+        if (!$currentUser['role']['perm_admin']) {
+            if (!$currentUser['role']['perm_org_admin']) {
+                return false;
+            } else {
+                if ($currentUser['organisation_id'] !== $user['organisation_id']) {
+                    return false;
+                }
+            }
+        }
+        return true;
     }
 
     /*