feat(save-git-folder): add new command to save git refs to .gitmodules.csv and update help-table

bin/save-git-folder

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+save-git-folder() {
+    echo "Save git refs to .gitmodules.csv."
+
+    local git_folders=$(ls-git-folder .)
+    echo "path,rev" > ".gitmodules.csv"
+    for git_folder in $git_folders; do
+        local commit_ref=$(git -C "$git_folder" rev-parse HEAD)
+        echo "$git_folder,$commit_ref" >> ".gitmodules.csv"
+    done
+}