feat(issue22/server-flask): Adds reply_to

`recipient` refers to FLASK_MAIL_RECIPIENT env var
which is the email address that receives all RFQ

server/app/api/routes.py

@@ -36,6 +36,7 @@ def send_rfq():
 
     msg = Message(
         "[ORDER HARDWARE - RFQ from %s]" % payload['email'],
+        reply_to=recipient,
         sender=payload["email"],
         recipients=[recipient])