The node and npm symlinks are not created in $target_dir as per the module documentation

The module documentation states that symlinks for `node` and `npm` would be created in `$target_dir` as part of the node.js installation but this is not the case. The only symlink that is created in `/usr/local/bin` (the default value for `$target_dir`) is a `node-${node_version}` symlink which points to `${node_unpack_folder}/bin/node`. `node` and `npm` symlinks are not created. My fix for this issue creates the following 2 symlinks in `$target_dir`:

* `node -> /usr/local/node/node-default/bin/node`
* `npm -> /usr/local/node/node-default/bin/npm`

The code is added to `init.pp` due to the fact that currently that's the code which creates the node-default symlink.