fixes #2863

Build, install and run:
gulp vscode-linux-packages
sudo dpkg -i out-linux/vscode-amd64.deb
code .

Installing the package does the following:
- Puts VSCode dir at /usr/share/code
- Puts code.sh launcher in /usr/bin
- Defines a .desktop file to properly integrate with the launcher

Fixes #2679

#2498

Fixes #2422: json extension ships dev node modules such as mocha and typescript that adds more than 13MB