Feature/project structure

[MichelMichels]

This PR is written to battle various issues.

• On page load of the GitHub project, I have to scroll on a 15" laptop multiple time to even see the README.md
• A lot of files in the root folder
• Inconsistent project naming
• Old files or projects lingering

Proposition:

I'd like to propose this project structure by David Fowler
This proposition would move all code related files to a src folder.

I also removed the UWP project, as this has seen no development in multiple years.

I renamed the mdresgen project to MaterialDesignToolkit.ResourceGeneration.

Warning

I tried my best to check if I didn't break anything, but the GitHub actions should definitely be thoroughly checked.

[abigailabbott]

hola antes entrando a mainDemo.wpf se encontraba la carpeta bin de ahi iba a Debug y de ahi iba a net472 y ahi uncontraba el archivo MaterialdesignDemo que era la aplicacion de los controles con sus codigos, ahora no encuentro eso