Feature Request: Option to Specify form CDN URL

[cadecairos]

Your FAQ suggests putting your S3 bucket behind a CDN, but the frontend has no way of respecting this configuration, and will continue showing the direct S3 url for resources to form creators.

I recommend providing a simple configuration option that lets you override the S3 domain in form links with a CDN url or custom URL. i.e. FormCDNURL: "https://forms.askcdndomain.com"