[Request]: Add legal copyright from Windows exe etc. to PackageInfo

### Plugin

package_info_plus

### Use case

I am using the package_info_plus-Addon to retrieve a PackageInfo instance and fill with this the properties of the [AboutDialog](https://api.flutter.dev/flutter/material/AboutDialog-class.html). Currently, I use the following properties to fill the following properties:

- appName -> applicationName
- 'v${version} (Build ${buildNumber})' -> applicationVersion

and I am missing the legal copyright-String from the executable of the app to use that for the applicationLegalese property. Can you please add to extract the LegalCopyright property from the Windows application executable and provide that value in a field within the PackageInfo class?

### Proposal

The plugin should also extract the value from the LegalCopyright property of the Windows executable and provide that as a field in the PackageInfo class. For Android, the contents for that field may come from a copyright text file (see https://ash12rai-weblearning.medium.com/copyright-profiles-android-studio-e476f6613274). For iOS, the copyright text may come from https://developer.apple.com/documentation/BundleResources/Information-Property-List/NSHumanReadableCopyright.

Beginne mit den Plattformimplementierungen von package_info_plus und der Klasse PackageInfo; das Issue nennt keine bestimmten Dateien oder Tests. Verfolge, wie Metadaten von Windows-Executable-Dateien derzeit verfügbar gemacht werden, und ermittle dann, wie die vorgeschlagenen Copyright-Quellen von Android und iOS in die API passen. Als erledigt gilt die Aufgabe, wenn PackageInfo den angeforderten Wert für legal-copyright bereitstellt und das Plattformverhalten definiert ist.

Vom Indexierungsmodell aus dem Issue-Text verfasst.