implemented user impersonization

frontend/src/routes/user/List.svelte

@@ -13,12 +13,24 @@
         const resp = await fetch(url,{credentials:'include'});
         if (resp.ok){
             const json = await resp.json();
-            for (let user of json) users.push(user);
+            for (let u of json) users.push(u);
         }
     });
+
+    async function impersonate(userId){
+        const url = `${location.protocol}//${location.host.replace('5173','8080')}/api/user/${userId}/impersonate`;
+        const resp = await fetch(url,{
+            method: 'POST',
+            credentials: 'include'
+        });
+        if (resp.ok){
+            const json = await resp.json();
+            for (let key of Object.keys(json)) user[key] = json[key];
+        }
+    }
 </script>
 
-<fieldset>
+<fieldset tabindex="0">
     <legend>{t('user.list')}</legend>
     <table>
         <thead>
@@ -38,6 +50,9 @@
                 <td>{u.email}</td>
                 <td>{u.language}</td>
                 <td>
+                    {#if user.permissions.includes('IMPERSONATE')}
+                    <button onclick={() => impersonate(u.id)}>{t('user.impersonate')}</button>
+                    {/if}
                     {#if user.permissions.includes('UPDATE_USERS')}
                     <button onclick={() => router.navigate(`/user/${u.id}/edit`)}>{t('user.edit')}</button>
                     {/if}