Fixes for Windows

On Windows systems the executable for node.js is now linked the right way.

Output Formatting

Improves output formatting

Refactoring and final checks

Adds a final check after the installation.

Now uses Symfony Process component instead of native exec function.

Also adds some console messages for better information.

Add download url template

Adds a download url template for the node.js binary.

Add Metadata

Metadata is added to the composer.json file.

First release

There are two features contained in this first release:

• Download of node.js
• Installation of yarn packge manager