Add installation script, default state file, and update README for Acer RGB control

acer-rgb

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+SOCK="/run/acer-rgbd.sock"
+
+if [[ $# -lt 1 ]]; then
+  echo "Usage:"
+  echo "  acer-rgb GET"
+  echo "  acer-rgb SET hidraw=/dev/hidraw2 dev=keyboard effect=static bright=80 r=255 g=0 b=0 zone=all"
+  exit 2
+fi
+
+cmd="$*"
+if command -v socat >/dev/null 2>&1; then
+  printf "%s\n" "$cmd" | socat - UNIX-CONNECT:"$SOCK"
+else
+  printf "%s\n" "$cmd" | nc -U "$SOCK"
+fi