[Feature]Add package download command

[Nigusu-Allehu]

Bug

Fixes: NuGet/Home#14608

Description

This PR implements the following design spec NuGet/Home#14495. It adds an implementation for the dotnet package download command. Audit is not implemented in this PR, and will be added in a follow up PR.

• Downloads NuGet packages
  The command allows users to download NuGet packages directly. By default, packages are downloaded to the current working directory (CWD). Users can optionally specify a different output directory.

Version Resolution

The ResolvePackageDownloadVersion method determines which version of a package to download from the provided sources:

• Exact version: If the user specifies a single version (not a range), the method checks each source until it finds that version.
  • If no version is specified -> the latest version is chosen.

The method returns both the resolved NuGetVersion and the SourceRepository it came from. If no valid version is found, an error is logged.

Usage Example

dotnet package download <PackageID> [-o <Path>]

• If no output directory is specified, the current working directory will be used.

PR Checklist

• Meaningful title, helpful description and a linked NuGet/Home issue
• Added tests
• Link to an issue or pull request to update docs if this PR changes settings, environment variables, new feature, etc. document package download command Home#14558

[aortiz-msft]

🕐

[Nigusu-Allehu]

@NuGet/nuget-client 👀

[nkolev92]

I just found one thing that I missed the previous review.

revoking review

[aortiz-msft]

See comments