Migrate zsh config to XDG base dir location

.zshenv still needs to live in ~ for bootstrapping, but everything else
is now squirrelled away in ~/.config/zsh instead.

Note that zplug still lives in ~/.zplug - it should be relocated too but
hasn't been yet.

.zsh/interactive/aliases

@@ -1,17 +0,0 @@
-#! zsh
-alias has_command='whence >/dev/null'
-alias ls="ls -F --color=auto"
-alias lsl="ls -lh"
-alias grep="grep --color=auto"
-alias egrep="egrep --color=auto"
-alias pseudo="sudo"
-if has_command xdg-open; then
-	alias ]='xdg-open'
-else
-	alias ]='open'
-fi
-
-# make sure ELinks can detect when it's in tmux
-alias elinks="STY= elinks"
-
-has_command hub && alias git=hub