Make the installation scripts install Node and tns

Currently our recommended quick installation is a three-step process: install Node, install tns, and then run our setup scripts. Even though those steps are relatively minimal, a surprising number of people get tripped up going through them. See https://github.com/NativeScript/docs/pull/585 for an example.

I want to propose that we change the installation scripts to install everything—Node, tns, and the various system requirements. The scripts could detect whether Node is installed, as to avoid undoing a user’s installation unknowingly.

A single script would simplify the documentation considerably, but it would probably be a non-trivial engineering effort. And with installers in the works perhaps this isn’t worth the effort. But I wanted to open this up to see what people think.

Thoughts?

Como a issue não nomeia arquivos, testes ou pontos de entrada, comece localizando os scripts de instalação e a documentação de configuração rápida. Uma alteração concluída faria com que os scripts instalassem Node, tns e os requisitos do sistema, detectando ao mesmo tempo uma instalação existente do Node, enquanto a documentação seria reduzida a um fluxo de configuração mais simples.