zsh: add /etc/zsh config files for easier unpacking

zsh-etcfiles/etc/zsh/zshenv

@@ -0,0 +1,14 @@
+# /etc/zsh/zshenv
+# zsh environment variables
+export XDG_CACHE_HOME="$HOME/.cache"
+export XDG_CONFIG_HOME="$HOME/.config"
+export XDG_DATA_HOME="$HOME/.local/share"
+export XDG_STATE_HOME="$HOME/.local/state"
+
+export ZDOTDIR="${XDG_CONFIG_HOME:-$HOME/.config}/zsh"
+
+# Shell settings
+export HISTCONTROL="ignoredups"
+export HISTFILE="${XDG_DATA_HOME:-$HOME/.local/share}/zsh/zsh_history"
+export HISTSIZE=20000
+export SAVEHIST=20000