Make zip folder from files downloaded under images

[Abhishek-kumar09]

So when all the certificates are sent to servers, it is required to zip all the files so that the zipped folder could be downloaded.

Steps to reproduce:

1. generate certificates from sample file from readme.md
2. edit image/pdf templates and send the files to servers
3. all the files would be sent to servers and saved under public/images

We have to zip the files and send it to response body