Make the installation scripts install Node and tns

Da im Issue keine Dateien, Tests oder Einstiegspunkte genannt werden, beginne damit, die Installationsskripte und die Dokumentation zur schnellen Einrichtung zu finden. Eine abgeschlossene Änderung würde dazu führen, dass die Skripte Node, tns und die Systemanforderungen installieren und dabei eine vorhandene Node-Installation erkennen, während die Dokumentation auf einen einfacheren Einrichtungsablauf reduziert wird.

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?