Proof of concept with Raw string literals

[pauldeen79]

Use C# raw string literals instead of T4 for templating.

If this works, we can remove all T4 stuff and the template parsing (token) stuff.
What will remain, is just the Runtime project (without template specific stuff) and the Cmd project (without template specific stuff)

Advantages:

• Easy debugging from your IDE of choice
• Intellisense from your IDE of choice
• No additional steps for references - .net core will take care of this
• We can throw away a lot of code

The proof of concept needs to include this:

• One template without reference to the Runtime project
• One template with reference to the Runtime project
• Try both with and without Model property on the root template - note that for testing, you will need the Runtime project
• Include child templates, and add code if needed to support this
• See if we can refactor those ugly Func delegates - especially if we need them. Just use standard DI with constructor injection.

See for more info:
https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/tokens/raw-string
https://devblogs.microsoft.com/dotnet/csharp-11-preview-updates/