CLI - allow second parameter to specify name of project/item template

Today you have to pass in the `-n` argument for the name of the project or template. For Example

```
dotnet new page -n MyPage -na MyNamespace
```

You almost always are going to specify -n for item templates, ideally you could just pass in a second parameter which is the next default, in this case `-n`.

This would pair great with https://github.com/dotnet/templating/issues/3008, which would allow for

```
dotnet new class MyClass
```