Refactoring: Remove Microsoft.TemplateEngine.Core dependencies on Microsoft.TemplateEngine.Abstractions

[JanKrivanek]

Contracts between Microsoft.TemplateEngine.Orchestrator.RunnableProjects and Microsoft.TemplateEngine.Core are not meant to be exposed publicly. However some of the Microsoft.TemplateEngine.Abstractions contracts (that are exposed) are being used - this create risk of breaking changes when working on changes in communication between RunnableProjectGenerator and Core.

We should:

• remove dependencies on Microsoft.TemplateEngine.Abstractions and Microsoft.TemplateEngine.Utils
• copy over any interfaces into Microsoft.TemplateEngine.Core.Contracts if needed
• review those dependencies and get rid of them alltogether if possible (instead of just duplicating)

As part of those changes we should make sure that ITemplateParameter changes for multichoice work (#4490) does not expose new parameter option AllowQuotelessLiterals to public abstractions (ITemplateParameter)