Add functionality to install modules during init

[Luke-Roy-IBM]

Install modules specified in package.json during initialisation as a alternative to packageing them. Detect if the node_modules directory is missing and installes the node modules.

[Luke-Roy-IBM]

Simple example that shows how the new functionality works

index.js

function main(args) {
    const oneLinerJoke = require('./one-liner-joke');
    let getRandomJoke = oneLinerJoke.getRandomJoke();

    return {
            body: getRandomJoke.body
        }
}

module.exports.main = main;

package.json

{
    "name": "my-action",
    "main": "index.js",
    "dependencies" : {
        "one-liner-joke" : "1.2.2"
    }
}