Send raw date to Fredrick vacation script

Allows to add the timezone to it to properly determine local sender time
and Fredrick's current time (if he's travelling within his home country,
that is).

ansible/roles/postfix/templates/services/fredrick-reply.sh.j2

@@ -38,9 +38,11 @@ JSON_BODY=$(echo -n "$BODY" | jq -R -s . | sed 's/\\n/\\\\n/g')
 FINAL_JSON=$(jq -r -c -n \
     --arg from "$SENDER" \
     --arg subject "$ORIGINAL_SUBJECT" \
-    --arg sent_at "$DATE_UNIX" \
+    --arg sent_at_unix "$DATE_UNIX" \
+    --arg sent_at_unparsed "$MESSAGE_DATE" \
     --argjson body "$JSON_BODY" \
-    '{sent_at: $sent_at, from: $from, subject: $subject, body: $body}')
+    '{sent_at_unix: $sent_at, sent_at_unparsed: $sent_at_unparsed,
+      from: $from, subject: $subject, body: $body}')
 
 FRED_RESPONSE=$(curl -X POST "$FREDRICK_ENDPOINT" \
     -H "Authorization: $FREDRICK_TOKEN" \