Updated all katas using C#9 and .NET 5.0

All code katas promoted to C#9 .NET 5.0.

Minor fixes and License updation

There are minor fixes and License change from Apache2.0 to MIT

Nuget package

Created Nuget Package with current release v1.11.0

Release 1.0.5

1. Upgraded .Net framework to 4.5
2. Added Another implementation of Reactive extensions to TDDKatas (https://github.com/dhelper)
3. Added Nuget Package - NUnit Test adapter (so, no other extension required to execute tests from within Visual Studio)-ref.:#12

Release 1.0.4

Modified all tests to run smoothly with VS2013