Convert from a Windows web service to a Linux web service

[sadukie]

This will involve creating a new app service since you can't easily change an app service from Linux to Windows.

• The environment variables use : on Windows - those change to __ (double underscore or "dunder") on Linux.
• Make sure to move the Custom domain over to the new app service.

[sadukie]

• Web App created with its own Linux app service plan (matches Windows in terms of pricing plan)
• Copied configuration variables from Windows to Linux and updated names to match Linux formatting

[sadukie]

CI/CD is almost there. We need to update the AZUREWEBAPPPUBLISHPROFILE in the GitHub Actions secrets with the publish profile for the Linux app service.

@ardalis - I don't have access to secrets, so I can't update this one. However, you can grab it from the devbetter-linux web app through the Azure portal and update it from there.