add example for testing typescript code with vscode-js-debug

[xddq]

Adding an example for debugging a typescript application using vimspector and vscode-js-debug. Typescript is a great language, but sadly the setup is hell. Debugging is no exception to this. This PR tries adding what would have been very beneficial for me when checking out vimspector for debugging typescript code. It contains a step by step description which can be followed by 'anyone'.

[puremourning]

This change is 

[xddq]

@puremourning Any updates on this? I went through your suggestions and made the changes accordingly