Created / Updated fields for clients (#3384)

* feat(backend): add created_at/updated_at to clients and maintain on create/update
backfill existing clients and set updated_at on mutations

* feat(frontend): carry created_at/updated_at in client models and round-trip via JSON

* feat(frontend): display Created and Updated columns in client table with proper date formatting

* i18n: add pages.inbounds.createdAt/updatedAt across all locales

* Update inbound.go

Remove duplicate code

web/html/component/aClientTable.html

@@ -278,4 +278,30 @@
     </a-badge>
   </a-popover>
 </template>
+<template slot="createdAt" slot-scope="text, client, index">
+  <template v-if="client.created_at">
+    <template v-if="app.datepicker === 'gregorian'">
+      [[ DateUtil.formatMillis(client.created_at) ]]
+    </template>
+    <template v-else>
+      [[ DateUtil.convertToJalalian(moment(client.created_at)) ]]
+    </template>
+  </template>
+  <template v-else>
+    -
+  </template>
+</template>
+<template slot="updatedAt" slot-scope="text, client, index">
+  <template v-if="client.updated_at">
+    <template v-if="app.datepicker === 'gregorian'">
+      [[ DateUtil.formatMillis(client.updated_at) ]]
+    </template>
+    <template v-else>
+      [[ DateUtil.convertToJalalian(moment(client.updated_at)) ]]
+    </template>
+  </template>
+  <template v-else>
+    -
+  </template>
+</template>
 {{end}}