Remove Spectre.Console.Cli from repository

* Move Spectre.Console.Cli to its own repository
* Update build script to use Cake.Sdk and .NET Make
* Remove StyleCop (unmaintained)
* Add linting using dotnet format
* Fix generator which was broken
* Update dependencies

README.md

@@ -11,7 +11,6 @@ It is heavily inspired by the excellent Python library, [Rich](https://github.co
 1. [Installing](#installing)
 1. [Documentation](#documentation)
 1. [Examples](#examples)
-1. [Sponsors](#sponsors)
 1. [Code of Conduct](#code-of-conduct)
 1. [.NET Foundation](#net-foundation)
 1. [License](#license)
@@ -52,26 +51,6 @@ https://spectreconsole.net
 To see `Spectre.Console` in action, please see the 
 [examples repository](https://github.com/spectreconsole/examples).
 
-## Sponsors
-
-The following people are [sponsoring](https://github.com/sponsors/patriksvensson)
-`Spectre.Console` to show their support and to ensure the longevity of the project.
-
-* [Rodney Littles II](https://github.com/RLittlesII)
-* [Martin Björkström](https://github.com/bjorkstromm)
-* [Dave Glick](https://github.com/daveaglick)
-* [Kim Gunnarsson](https://github.com/kimgunnarsson)
-* [Andrew McClenaghan](https://github.com/andymac4182)
-* [C. Augusto Proiete](https://github.com/augustoproiete)
-* [Viktor Elofsson](https://github.com/vktr)
-* [Steven Knox](https://github.com/stevenknox)
-* [David Pendray](https://github.com/dpen2000)
-* [Elmah.io](https://github.com/elmahio)
-* [Tom Kerkhove](https://github.com/tomkerkhove)
-
-We really appreciate it.  
-**Thank you very much!**
-
 ## Code of Conduct
 
 This project has adopted the code of conduct defined by the Contributor Covenant to clarify expected behavior in our community.