Add or extend example with own vscode service implementation

[kaisalmen]

Add or extend an example to show how a service can be implemented and used:
https://github.com/CodinGame/monaco-vscode-api#monaco-standalone-services

[kaisalmen]

@CGNonofr any good idea what we could add here as a demonstrator to an existing example?

[CGNonofr]

The notification service is probably a good candidate

[kaisalmen]

@CGNonofr I started to implement a notification service stub and I now the init fails. What am I missing or am I doing it completely wrong?

[CGNonofr]

@CGNonofr I started to implement a notification service stub and I now the init fails. What am I missing or am I doing it completely wrong?

I missed that one

Did you import service-overrides/configuration without actually using the service override?