How to replicate the functionality of the ServiceNow 'Download All' button!

Recently one of my customers wanted to replicate the functionality of the ServiceNow 'Download All' button available via the attachment paperclip. But the request was to add the related list sys_attachment to the application form and provide the user with a List Banner Button UI Action called 'download all attachments (zip)'.  To achieve this I got access to the OOB UI action and manipulated it to achieve the requested functionality.  I am sharing this with everyone because I was not able to find this solution anywhere and I do not want anyone to waste their time trying to figure this out.

Name: download all attachments (zip)

Table: sys_attachment

Active: true

Show update: true

Client: true

List banner button: true

Onclick: downloadAllAttachments()