Add a /view page

[fdb]

This page shows the sketch without any extra elements. It renders the content and writes it out directly into the page.

• [ ] Correct /view routing using Firebase
• [ ] Support random seed in URL bar
• [ ] Add support for sketches that use import (e.g. sketch -L5wbLHtyOhej49zKNMh)

This implements #32 .

To try locally, use serve -s, then open http://localhost:5000/view.html?id=-L4uLB99JzFHMPcVoiTm

[dhruvramdev]

Hi @fdb , I wanted to know whether you would anyone to complete this PR or you want to complete it yourself?