Hints for smb4k in main

Warnings

• metainfo-validation-issue
  Validation of the metainfo file found a problem: The component ID is not a reverse domain-name. Please update the ID and that of the accompanying .desktop file to follow the latest version of the Desktop-Entry and AppStream specifications and avoid future issues.
• screenshot-download-error
  Error while downloading screenshot from 'https://sourceforge.net/p/smb4k/screenshot/main_window_1-1-1_hp.png': HTTP request returned status code 404 (Not Found)
  This might be a temporary server issue.
• screenshot-download-error
  Error while downloading screenshot from 'https://sourceforge.net/p/smb4k/screenshot/plasmoid.png': HTTP request returned status code 404 (Not Found)
  This might be a temporary server issue.