Commands delete, sign and verify in Tools DotNet and NuGet

[ricaun]

Update tools DotNet and NuGet to include the following commands related to NuGet packages.

• dotnet nuget delete: Allow to delete package, in nuget.org the package is unlisted. (Useful to hide pre-release versions.)
• dotnet nuget sign: Allow to sign a package using a certificate file.
• dotnet nuget verify: Allow to verify if the package is sign.

The dotnet nuget and NuGet.exe is basically the same thing.

• nuget delete
• nuget sign
• nuget verify

I confirm that the pull-request:

• Follows the contribution guidelines
• Is based on my own work
• Is in compliance with my employer

[Nice3point]

Thanks