Fixes#21291, allowing icons and other missing attributes to appear for
NuGet packages from inside Visual Studio like they do with GitHub Nuget
packages.
Adds additional NuGet package information, particularly `IconURL`, to
bring the Gitea NuGet API more in-line with GitHub's NuGet API.
ref: https://learn.microsoft.com/en-us/nuget/api/search-query-service-resource