We no longer require Cake build nor we use it extensively!
Update Azure Pipelines (CI YAML) Script to be more modern and runnable across platforms.
Replaced the headers check with a PowerShell script mimicking the Cake script's `UpdateHeaders` task functionality.
See https://developercommunity.visualstudio.com/t/1568612.
We can consider reverting this once this has been fixed.
Used "dotnet" to be consistent with repo name. Using "NET", "dotNet" or variations would've just been wrong, so "dotnet" seemed like the best alternative.