Dotnet new dir lang/type

[enricosada]

ref #655

add dir and lang/type arguments, full is dotnet new dir lang/type.
the --type and --lang works too.

Default are:

• dir empty => .
• lang/type empty => csharp/console

so dotnet new = dotnet new . csharp/console like current behaviour

If dir exists => error

Some examples:

PS D:\github\cli\prova> dotnet new hello_world
Created new C# Console project in D:\github\cli\prova\hello_world.

PS D:\github\cli\prova> dotnet new hello2 console
Created new C# Console project in D:\github\cli\prova\hello2.

PS D:\github\cli\prova> dotnet new hello2 fsharp/console
Directory hello2 already exists

PS D:\github\cli\prova> dotnet new hello3 fsharp/console
Created new F# Console project in D:\github\cli\prova\hello3.

PS D:\github\cli\prova> dotnet new hello5 --type console
Created new C# Console project in D:\github\cli\prova\hello5.

PS D:\github\cli\prova> dotnet new . console
Created new C# Console project in D:\github\cli\prova.

PS D:\github\cli\prova> dotnet new --lang f# hello7 console
Created new F# Console project in D:\github\cli\prova\hello7.

PS D:\github\cli\prova> dotnet new --lang f# hello7 suave
Unrecognized type: suave
Avaiable types for F# :
- Console

ready for review /cc @blackdwarf

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This change is

[enricosada]

@dotnet-bot test Ubuntu Debug please

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i think i need to wait for Ubuntu to become green again

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@dotnet-bot test Ubuntu Debug Build please

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@dotnet-bot test Ubuntu Release Build please

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ok @blackdwarf @piotrpMSFT that's ready to review/merge

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ping @blackdwarf because i think it's nice if we can scaffold a library type too instead of app only, it's really useful (ppl can learn basic usage of project.json with this tool, like library/app)

and dir is nice for demo and hello world 😄

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try to unstuck jenkins

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rebased and ready

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closed in favor of #2052