Some NuGet package enhancements (#30280)

Fixes #30265

1. Read second type of dependencies
2. Render `Description` and `ReleaseNotes`

old:

![grafik](abac057c-11cd-4d25-b196-01ff899d948e)

new:

![grafik](35302273-740c-481a-a031-1f80d2d7d336)

The NuGet spec does not specify what kind of text can be stored in the
description but we can best guess markdown. The official NuGet registry
just [converts the newlines to html
lines](https://www.nuget.org/packages/rb.Firefox#readme-body-tab).

3. Extract and render the readme. This is the new and better place to
store larger text than in the description. The content is markdown.

![grafik](f442264e-3735-4b55-92c4-3b89a8ebafb0)

---------

Co-authored-by: Benjamin Heemann <benjamin.heemann@raith.de>

modules/packages/nuget/metadata.go

@@ -58,6 +58,7 @@ type Package struct {
 type Metadata struct {
 	Description              string                  `json:"description,omitempty"`
 	ReleaseNotes             string                  `json:"release_notes,omitempty"`
+	Readme                   string                  `json:"readme,omitempty"`
 	Authors                  string                  `json:"authors,omitempty"`
 	ProjectURL               string                  `json:"project_url,omitempty"`
 	RepositoryURL            string                  `json:"repository_url,omitempty"`
@@ -71,6 +72,7 @@ type Dependency struct {
 	Version string `json:"version"`
 }
 
+// https://learn.microsoft.com/en-us/nuget/reference/nuspec
 type nuspecPackage struct {
 	Metadata struct {
 		ID                       string `xml:"id"`
@@ -80,6 +82,7 @@ type nuspecPackage struct {
 		ProjectURL               string `xml:"projectUrl"`
 		Description              string `xml:"description"`
 		ReleaseNotes             string `xml:"releaseNotes"`
+		Readme                   string `xml:"readme"`
 		PackageTypes             struct {
 			PackageType []struct {
 				Name string `xml:"name,attr"`
@@ -89,6 +92,11 @@ type nuspecPackage struct {
 			URL string `xml:"url,attr"`
 		} `xml:"repository"`
 		Dependencies struct {
+			Dependency []struct {
+				ID      string `xml:"id,attr"`
+				Version string `xml:"version,attr"`
+				Exclude string `xml:"exclude,attr"`
+			} `xml:"dependency"`
 			Group []struct {
 				TargetFramework string `xml:"targetFramework,attr"`
 				Dependency      []struct {
@@ -122,14 +130,14 @@ func ParsePackageMetaData(r io.ReaderAt, size int64) (*Package, error) {
 			}
 			defer f.Close()
 
-			return ParseNuspecMetaData(f)
+			return ParseNuspecMetaData(archive, f)
 		}
 	}
 	return nil, ErrMissingNuspecFile
 }
 
 // ParseNuspecMetaData parses a Nuspec file to retrieve the metadata of a Nuget package
-func ParseNuspecMetaData(r io.Reader) (*Package, error) {
+func ParseNuspecMetaData(archive *zip.Reader, r io.Reader) (*Package, error) {
 	var p nuspecPackage
 	if err := xml.NewDecoder(r).Decode(&p); err != nil {
 		return nil, err
@@ -166,6 +174,28 @@ func ParseNuspecMetaData(r io.Reader) (*Package, error) {
 		Dependencies:             make(map[string][]Dependency),
 	}
 
+	if p.Metadata.Readme != "" {
+		f, err := archive.Open(p.Metadata.Readme)
+		if err == nil {
+			buf, _ := io.ReadAll(f)
+			m.Readme = string(buf)
+			_ = f.Close()
+		}
+	}
+
+	if len(p.Metadata.Dependencies.Dependency) > 0 {
+		deps := make([]Dependency, 0, len(p.Metadata.Dependencies.Dependency))
+		for _, dep := range p.Metadata.Dependencies.Dependency {
+			if dep.ID == "" || dep.Version == "" {
+				continue
+			}
+			deps = append(deps, Dependency{
+				ID:      dep.ID,
+				Version: dep.Version,
+			})
+		}
+		m.Dependencies[""] = deps
+	}
 	for _, group := range p.Metadata.Dependencies.Group {
 		deps := make([]Dependency, 0, len(group.Dependency))
 		for _, dep := range group.Dependency {