Improve source package with T4 install experience

[dadhi]

• Automate manual step of copying T4 files
• Automate copying of package dependencies

NuGet/Home#4837

[dadhi]

Replacing T4 is also a good alternative.

[dadhi]

Related #101

[dadhi]

Consider https://github.com/AArnott/CodeGeneration.Roslyn

[dadhi]

Consider using mono t4 implementation which is actively developed and can be referenced as a CLI tool: https://github.com/mono/t4

[dadhi]

Or may be this: https://github.com/Muchiachio/Genny

[dadhi]

Use https://github.com/Konard/T4GenericsExample as an example with https://github.com/mono/t4 CLI tool reference

[dadhi]

Related mono/t4#70

[dadhi]

Another good doc to check https://medium.com/@christopher.r.froehlich/code-generation-fail-an-all-the-kings-horses-tragedy-36dcd412ad05

[dadhi]

Another example with step by step guide working on .NET Core 3.0 https://github.com/dadhi/T4Sample

[dadhi]

T4 nuget package http://diegogiacomelli.com.br/deploying-a-t4-template-with-dotnet-pack/

[dadhi]

Content-only NuGet package: https://medium.com/@attilah/source-code-only-nuget-packages-8f34a8fb4738