How to add a repo to a workspace via URL?

## What is your suggestion?

I have a locally hosted installation "https://coder.localhost/?..."
I want to go to github get an URL and clone/open via url
like "https://coder.localhost/?workspace=https://github.com/coder/code-serve" or something.

## Why do you want this feature?

I can then write a chrome plugin for one click open in coder functionality.

## Are there any workarounds to get this functionality today?

Just manually.

## Are you interested in submitting a PR for this?