Configuration from environment variables

[nblumhardt]

Serilog's ASP.NET Core configuration provider supports environment variables alongside JSON syntax.

https://github.com/serilog/serilog-settings-configuration#environment-variables

E.g. on Windows:

set Serilog:MinimumLevel=Debug

Alongside Show <appSettings> config and Show appsettings.json config, what do you think about listing Show CMD.exe config, Show bash config and/or Show PowerShell config?