Add per-user zsh script loading

sh/load.sh

@@ -1,6 +1,19 @@
 TOOLKIT=/etc/toolkit
 
-# Sources custom shell scripts
-for sh in ${TOOLKIT}/sh/custom/*.sh; do
+load_scripts_in_dir() {
+  for sh in ${TOOLKIT}/sh/custom/*.sh; do
     test -r "$sh" && . "$sh"
-done
+  done
+}
+
+create_dir_if_not_exists() {
+  if [[ ! -d $1 ]]; then
+    mkdir -p $1
+  fi
+}
+
+# Load custom scripts (aliases, variables, etc...)
+load_scripts_in_dir $TOOLKIT/sh/custom_scripts
+
+# Scripts ran to modify existing toolkit updates
+load_scripts_in_dir $TOOLKIT/sh/patch_scripts