Support additional attributes in <iframe> tag

mohit_aghera → closed merge request !6

mohit_aghera → reopened merge request !6

mohit_aghera → closed merge request !6

1) I like the "sandbox" attribute, but its dangerous.
[sandbox atrribute](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe#sandbox)

If its set, then the default is very restrictive (no forms, no downloads, no scripts, no alerts, no popups, ...)

We should discuss what we suggest as "default" Options to enable.

I would suggest at minimum: "allow-downloads,allow-forms"

What is your opinion?

2) "reffererpolicy" would be OK with the default "strict-origin-when-cross-origin" (this is the normal browser default too)

Sounds like this needs more work/discussion.

Maybe worth breaking out into 2 separate as reffererpolicy seems less problematic.