Remove dependency on OSS repositories

[arudell]

Description

This pull request includes several changes to improve the handling of the Get-NetView module, clean up configuration files, and streamline the build process. The most important changes include adding error handling for the Invoke-SdnGetNetView function, removing unnecessary package dependencies, and cleaning up the build scripts.

Error Handling and Module Import:

• src/SdnDiagnostics.psm1: Added a try-catch block around the Invoke-SdnGetNetView call to handle errors gracefully and log warnings.
• src/modules/SdnDiag.Common.psm1: Modified the Invoke-SdnGetNetView function to import the Get-NetView module directly, check for its availability, and log warnings if the module is outdated. [1] [2]

Configuration Cleanup:

• nuget.config: Removed the nuget.config file to eliminate unnecessary package source definitions and reduce potential supply chain vulnerabilities.
• packages.config: Removed the packages.config file to clean up package dependencies.
• SdnDiagnostics.nuspec: Removed the external package dependency on Get-NetView.

Build Script Improvements:

• .build/build.ps1: Removed unnecessary comments and streamlined the build script.
• .build/package.ps1: Cleaned up the package script by removing an unnecessary blank line.
• build.ps1: Removed the restore step from the build script as it is no longer needed.

Change type

• Bug fix (non-breaking change)
• Code style update (formatting, local variables)
• New Feature (non-breaking change that adds new functionality without impacting existing)
• Breaking change (fix or feature that may cause functionality impact)
• Other

Checklist:

• My code follows the style and contribution guidelines of this project.
• I have tested and validated my code changes.