Warn about the backup feature

src/components/settings/Backup.vue

@@ -1,6 +1,12 @@
 <template>
     <div>
         <div class="my-4">
+            <div class="alert alert-warning" role="alert" style="border-radius: 15px;">
+                {{ $t("backupOutdatedWarning") }}<br />
+                <br />
+                {{ $t("backupRecommend") }}
+            </div>
+
             <h4 class="mt-4 mb-2">{{ $t("Export Backup") }}</h4>
 
             <p>

src/languages/en.js

@@ -580,4 +580,6 @@ export default {
     goAlertInfo: "GoAlert is a An open source application for on-call scheduling, automated escalations and notifications (like SMS or voice calls). Automatically engage the right person, the right way, and at the right time! {0}",
     goAlertIntegrationKeyInfo: "Get generic API integration key for the service in this format \"aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee\" usually the value of token parameter of copied URL.",
     goAlert: "GoAlert",
+    backupOutdatedWarning: "Deprecated: Since a lot of features added and this backup feature is a bit unmaintained, it cannot generate or restore a complete backup.",
+    backupRecommend: "Please backup the volume or the data folder (./data/) directly instead.",
 };