Added script hooks for unfinished custom configurations.

- These scripts default to calling out to scripts of the same name as
  defined by the custom configuration project (i.e.
  `$MAC_OS_CONFIG_PATH`).
- This helps ensure the scripts in this project can be run
  appropriately even if the custom configuration project hasn't fully
  implemented all scripts yet.
- This also helps illustrate what scripts are necessary when creating a
  custom configuration.

bin/setup_software

@@ -0,0 +1,18 @@
+#! /usr/bin/env bash
+
+# DESCRIPTION
+# Sets up and launches (if necessary) installed software.
+
+# SETTINGS
+set -o nounset
+set -o errexit
+set -o pipefail
+IFS=$'\n\t'
+SCRIPT_PATH="$MAC_OS_CONFIG_PATH/bin/setup_software"
+
+# EXECUTION
+if [[ -x "$SCRIPT_PATH" ]]; then
+  "$SCRIPT_PATH"
+else
+  printf "WARNING: Software setup script does not exist or is not executable.\n"
+fi