Fixes for onlinemeetings going v1.0 & OneNote fix

[jthake]

Updated readme to make it clearer on a few areas after doing the steps myself. Primarily around SSL cert approach in App Service.

Added a fix for checking whether the OneNote notebook actually exists and if not creates it.

Moved from using /beta/app/OnlineMeetings to /v1.0/me/OnlineMeetings and switched to use the SDK rather than HttpRequest method.

[jthake]

@TBag you'll also notice if you use the .\PublishWebapp.ps1 with the settings values removed. The web app gives you a 404 when you run in a browser. I had to populate the appsettings.json with my environment variables for this to work correctly. Can you please validate for me?

[TBag]

Let's sync on the script today, not sure what you're referring to.