Add design mock-up preview side-by-side to the device previews

[manojVivek]

Discussed in https://github.com/responsively-org/responsively-app/discussions/640

^{Originally posted by NormanJaimes November 11, 2021} Yes, I know the "function" of the tool.

But I would like to add another feature. And is a "project preview tab". For example. I'm working on a project with adobe XD, and the "design" link is online. So To watch or see this design I have to go to Google and open the link of the project. So it could be great if you could add these features. to become "responsively" as All-in-one tool. So I could preview or watch the design in the same "responsively app" without going to the "internet browser" or switching between apps...

Thanks, guys... 💪