Update packages

[ronaldruzicka]

I updated all packages from our devstack to the latest version, except eslint-plugin-jsx-a11y, which was not compatible with other packages, but it works with version 5.1.1.

From now on, we should use node 8.2.1 and npm 5.3.0 and higher.

Removed yarn.lock, because npm v5 adds it's own package-lock.json.

Changed error message format in js task, because it was not showing all message, which resulted in confusions with debugging the issue

Replaced module.js with suffix.js, because it was not initiated in app.js and therefore doing nothing.

Moved autoprefixer settings into package.json as recommedned

[vbulant]

Regarding the node version, you should reflect that in package.json ("engines" key). It used for node version checking in https://github.com/actum/gulp-dev-stack/blob/master/gulp/environment.js

[vbulant]

I think you can delete the suffix.js (module.js) altogether as there is already the cookieLaw module which is both an example and production ready.

[ronaldruzicka]

@vbulant I already did, it is there:

"engines": {
    "node": ">=8"
}