Simple directions for dockerless install

[neubig]

What problem or use case are you trying to solve?

It is relatively easy to get started if you have docker, but it's not easy to get started without docker.

Describe the UX or technical implementation you have in mind

We can start with our local runtime directions: https://docs.all-hands.dev/modules/usage/runtimes/local
But cover the entirety of the "getting started" process.

Additionally, we should consider making vscode, jupyter, and the browser optional dependencies.

If you find this feature request or enhancement useful, make sure to add a 👍 to the issue