Replacement for `dnu commands install` in dotnet: dotnet add tool

[peterblazejewicz]

I've a face palm moment today as I was using my keyboard muscle memory trying to add 'dotnet add package Microsoft.DotNet.Watcher.Toolsnaively and using them after restore. As kindly explained to me: https://github.com/aspnet/DotNetTools/issues/297#issuecomment-303191445 I'm supposed to edit.csproj` and insert relevant tooling information into separate group:

<ItemGroup>
    <DotNetCliToolReference Include="Microsoft.DotNet.Watcher.Tools" Version="1.0.0" />
    <DotNetCliToolReference Include="Microsoft.Extensions.SecretManager.Tools" Version="1.0.0" />
  </ItemGroup>

Could you please consider to adding back a nice, quick way to script dependency installation back to project file? (dotnet add tool [.....]?)
Thanks!

[natemcmaster]

This issue was moved to dotnet/cli#6661