Add --skip-elm-format flag

[lydell]

This is useful in Dockerfiles:

• There’s no need for elm-format in a build. Installing it and running it slows the build down. This is true for other builds than Docker ones, too.

• elm-format does not work in all Docker images. In Alpine images, it does not work at all. The default node image uses Debian Stretch, but elm-format 0.8.4 requires Debian Buster. Sometimes it’s easier to disable elm-format than to switch image. Dillon also mentioned that elm-format 0.8.4 is also causing issues in the default Netlify build.

This PR adds a --skip-elm-format flag that skips running elm-format on the generated output.

Unfortunately, the generated Elm code is not syntactically valid. The Elm compiler does not accept it, but elm-format’s more lenient parser does. So I had to add a space here and there in the code generation so the output of a elm-graphql --skip-elm-format run is still valid. I think it’s good not to rely on elm-format’s parser anyway.

I recommend reviewing commit by commit in order not to get lost in the sea of no-format-example/ files.

[dillonkearns]

This is perfect, thank you very much Simon! 🙏