Add possibility to prefix EnvVar Names

we are using `Vite` to run our react frontends. adding those with AddNpmApp works well, but the problem is, that the environment variables are not available to the frontend.

as per [Vite Documentation](https://vitejs.dev/guide/env-and-mode.html#env-files) environment variables are only available in vite, if the name begins with `VITE_`.

so I suggest to add a `WithEnvironmentPrefix(string prefix)` method to set the prefix for all the exposed environment variables like service URLs, Otlp endpoints etc.