GitHub and CI integration

[ulrikstrid]

As discussed on Discord.

It would be a really cool experience if you could "create new project" and that forks/copies a starter project to your GitHub account.
This starter includes everything you need including CI setup.
You then go ahead and edit your code in the playground and have live updates as you work on it.
When you're done for the session/done with one feature you save the code. This creates a commit on GitHub and kicks off the CI. A few minutes later you have a compiled program that you can run natively on your computer that looks and behaves the same as the web version in the playground.

Azure DevOps recently added login with GitHub support and if we can only ask for 1 login that would be great. If that doesn't work we could do a setup where the playground opens a PR to the base project and then CI builds the PR but there might be drawbacks to this.