X11: Move pieces from i3 and zshenv into xinitrc

Move everything that is desirable independent of the WM or shell into
xinitrc.
Move .Xresources and .Xmodmap into .config/X11.
Remove all unneeded GNOME bits from i3 config.
Make compositor launch script portable.
Add locker symlink and launch.sh similar to the compositor.

.config/compton/launch.sh

@@ -1,7 +1,10 @@
 #!/bin/sh
 
+basedir="$(cd "$(dirname "$0")" && pwd -P)"
+compositor="$(basename "$basedir")"
+
 if [ "$1" = "-k" ];  then
-	killall -q compton
-elif ! pgrep -ax compton >/dev/null 2>&1; then
-	compton --config "${XDG_CONFIG_HOME:-$HOME/.config}/compton/compton.conf" -b
+	killall -q "$compositor"
+elif ! pgrep -ax "$compositor" >/dev/null 2>&1; then
+	"$compositor" --config "$basedir/$compositor".conf -b
 fi