docs: add Japanese translate documents (#1812)

* docs: add Japanese documents (`ja/docs`)

* docs: add Japanese documents (`ja/codes`)

* docs: add Japanese documents

* Remove pythontutor blocks in ja/

* Add an empty at the end of each markdown file.

* Add the missing figures (use the English version temporarily).

* Add index.md for Japanese version.

* Add index.html for Japanese version.

* Add missing index.assets

* Fix backtracking_algorithm.md for Japanese version.

* Add avatar_eltociear.jpg. Fix image links on the Japanese landing page.

* Add the Japanese banner.

---------

Co-authored-by: krahets <krahets@163.com>

ja/codes/cpp/chapter_stack_and_queue/stack.cpp

@@ -0,0 +1,41 @@
+/**
+ * File: stack.cpp
+ * Created Time: 2022-11-28
+ * Author: qualifier1024 (2539244001@qq.com)
+ */
+
+#include "../utils/common.hpp"
+
+/* ドライバーコード */
+int main() {
+    /* スタックを初期化 */
+    stack<int> stack;
+
+    /* 要素プッシュ */
+    stack.push(1);
+    stack.push(3);
+    stack.push(2);
+    stack.push(5);
+    stack.push(4);
+    cout << "Stack stack = ";
+    printStack(stack);
+
+    /* スタックトップ要素にアクセス */
+    int top = stack.top();
+    cout << "Top element of the stack top = " << top << endl;
+
+    /* 要素ポップ */
+    stack.pop(); // 戻り値なし
+    cout << "Element popped from the stack = " << top << ", after popping";
+    printStack(stack);
+
+    /* スタックの長さを取得 */
+    int size = stack.size();
+    cout << "Length of the stack size = " << size << endl;
+
+    /* 空かどうかを判定 */
+    bool empty = stack.empty();
+    cout << "Is the stack empty = " << empty << endl;
+
+    return 0;
+}