Mime handling for Void Linux .xbps packages

Making a start to support Void Linux .xbps packages in Easy. The *.xbps package file will be recognised, displaying in the file manager with an appropriate icon and action when left-click or right-click offer to install. Here are the commits:

https://github.com/bkauler/woofq/commit/a25337351a25e351476a4adf7e98fcdc224be1d5

https://github.com/bkauler/woofq/commit/23a4b5fde475bf577f02fa608f2a394adbbb59ca

This is just the start.   

Tags: easy