add `elm new` for improved onboarding experience

[Johannes Barre]

I think, it would be helpful for newcomers to have a command similar to rails new or lein new to generate a skeleton app. For example, it could:

• create a src/Main.elm with a bare beginnerProgram (or a very simple program, like a counter). This should have comments to explain the parts
• Install elm-lang/html and dependencies (generate a elm-package.json)
• Possibly generate a README to help people of the ground
• Print a message explaining what it did and how to go from here (e.g. "run elm reactor and go to http://localhost:8000/src/Main.elm")

What do you think?

[Process Bot]

Thanks for the issue! Make sure it satisfies this checklist. My human colleagues will appreciate it!

Here is what to expect next, and if anyone wants to comment, keep these things in mind.

[Simone Vittori]

Hey @iGEL! I created elm-new which does pretty much what you're describing.

Does that help you in any way?

[Evan Czaplicki]

There'll be something like this in the next version of Elm!