feat: connectivity view: quota for all transports (#7630)

- **show quota of all relays**
- **remove `DC_STR_STORAGE_ON_DOMAIN` stock string**
- renames the quota section to "Relay Capacity" until we come up with a
better name in
https://github.com/chatmail/core/issues/7580#issuecomment-3633803432

closes #7591

<img width="300" alt="image"
src="https://github.com/user-attachments/assets/1909dccd-e6b3-42e6-963f-004b2b464db7"
/> <img width="300" alt="image"
src="https://github.com/user-attachments/assets/1e97e67b-e0ed-492b-95a0-6ef12595abe4"
/>

src/scheduler.rs

@@ -481,7 +481,7 @@ async fn inbox_fetch_idle(ctx: &Context, imap: &mut Imap, mut session: Session)
     }
 
     // Update quota no more than once a minute.
-    if ctx.quota_needs_update(60).await
+    if ctx.quota_needs_update(session.transport_id(), 60).await
         && let Err(err) = ctx.update_recent_quota(&mut session).await
     {
         warn!(ctx, "Failed to update quota: {:#}.", err);