Replace QProcess with KArchive to view archive contents.

KArchive is now used instead of running zipinfo, unrar and tar via QProcess to get the list of files in the archive or to extract the preview of the .kra file.

1. .7z files are now supported
2. Support for .rar files has been removed as they are not supported by KArchive.

I'm looking for a way to delete !isDir! but I don't know how to do it, do you have any suggestions?

        if (entry.isDir()) {
            //"!isDir!" is used to identify the folders in qml.
            folderList.append(QStringLiteral("!isDir!") + entry.fileName());
        } else {
            fileList.append(entry.fileName());
        }

I've made some progress using QVariantMap. I will remove "!isDir!" as soon as I can.

Fixed