[feature] Add bookmarklet

[dadatuputi]

A bookmarklet is a simple javascript anchor element that users can drag to the bookmark that will run on the page when clicked.

Use case:

1. User drags the anchor "Summarize with smry.ai" to their bookmark bar
2. User goes to a website they want to use with smry.ai
3. User clicks the bookmarklet, which loads the smry.ai url for the website

It's really basic javascript:

javascript:window.location.href=`https://smry.ai/${window.location.href}`;

You can test it out on this fiddle: https://jsfiddle.net/zLdgbvcm/

I'm happy to submit as a PR if you want.

[mrmps]

Please submit as a PR!

[mcdoubleyou]

Bookmarklets won't work on mobile?
Thanks!