[arch-dev-public] Dropping xarchiver from [extra]

[Evangelos Foutras]

Reason is that it's buggy and has been unmaintained for close to 3
years. There's currently one open bug about it [1], which I'm not
willing to troubleshoot.

The suggested alternative application is GNOME's archive tool, File Roller.

Unless anyone objects, I'm going to move it to the AUR in a few days.

[1] https://bugs.archlinux.org/task/29650