packaging: Move unit alias to install section

Otherwise there will be

  systemd[1]: /usr/lib/systemd/system/tuwunel.service:5: Unknown key 'Alias' in section [Unit], ignoring.

on startup. See `systemd.unit(5)`.

Signed-off-by: Guido Günther <agx@sigxcpu.org>

rpm/tuwunel.service

@@ -2,7 +2,6 @@
 Description=Tuwunel Matrix homeserver
 Wants=network-online.target
 After=network-online.target
-Alias=matrix-tuwunel.service
 Documentation=https://tuwunel.chat/
 
 [Service]
@@ -63,3 +62,4 @@ StartLimitBurst=5
 
 [Install]
 WantedBy=multi-user.target
+Alias=matrix-tuwunel.service