Organize Manjaro xfce system settings dotfiles.

[tyn1998]

Not like git or tmux which has one or two dotfiles (or dotdirectory) under user directory ~, Manjaro xfce's system settings such as windows management and keymapping are distributed in different paths. So I should work out the correspondence between all important system settings and their dotfiles, and then organize the dotfiles into one directory called Manjaro xfce.