Handle verbosity in extract_appimage for non-returning errors (#1233)

[aoxolotl]

Added check if verbose flag is set for fprintf ("File exists and file size matches, skipping".). Fixes #1233

[probonopd]

Thanks @aoxolotl. Since we will be switching to https://github.com/AppImage/type2-runtime soon, you might want to send a PR there as well. Thanks!

[aoxolotl]

Thanks for the review! Can look into type-2 runtime as well 👍