install nodejs/npm on workers

[SethTisue]

for Scala.js. requested by @sjrd at scala/community-build#276

[SethTisue]

I provisionally deployed this. here's what we see now on the workers:

ubuntu@ip-172-31-12-38:~$ nodejs --version
v4.2.6
ubuntu@ip-172-31-12-38:~$ node --version
The program 'node' is currently not installed. You can install it by typing:
sudo apt install nodejs-legacy
ubuntu@ip-172-31-12-38:~$ npm --version
The program 'npm' is currently not installed. You can install it by typing:
sudo apt install npm

the node version seems a bit old

[SethTisue]

the Chef cookbook we're using supports different installation methods. the default method is to use apt, and I checked that sudo apt-get update followed by apt list --upgradable doesn't show a newer version, so I guess that's just what the version of Ubuntu we're using offers?

@sjrd is it sufficient?

[SethTisue]

also does nodejs vs node matter?

trying a new test run at https://scala-ci.typesafe.com/job/scala-2.11.x-integrate-community-build/300/console

[sjrd]

Yes, nodejs vs node matters. By default, Scala.js looks for node, but the nodejs thing is a known issue for Ubuntu, for which we have a workaround: add jsEnv := NodeJSEnv(executable = "nodejs").value in the settings of projects that need to run with Node.js. I'll update the PR on community-builds.

[SethTisue]

merged since latest community build runs are green.

but @adriaanm, you might want to give the Chef changes a once-over and make sure I didn't cargo-cult in some nonsense

[adriaanm]

LGTM