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/deque.cpp

@@ -0,0 +1,46 @@
+/**
+ * File: deque.cpp
+ * Created Time: 2022-11-25
+ * Author: krahets (krahets@163.com)
+ */
+
+#include "../utils/common.hpp"
+
+/* ドライバーコード */
+int main() {
+    /* 両端キューを初期化 */
+    deque<int> deque;
+
+    /* 要素エンキュー */
+    deque.push_back(2);
+    deque.push_back(5);
+    deque.push_back(4);
+    deque.push_front(3);
+    deque.push_front(1);
+    cout << "Double-ended queue deque = ";
+    printDeque(deque);
+
+    /* 要素にアクセス */
+    int front = deque.front();
+    cout << "Front element of the queue front = " << front << endl;
+    int back = deque.back();
+    cout << "Back element of the queue back = " << back << endl;
+
+    /* 要素デキュー */
+    deque.pop_front();
+    cout << "Front element dequeued = " << front << ", after dequeuing from the front";
+    printDeque(deque);
+    deque.pop_back();
+    cout << "Back element dequeued = " << back << ", after dequeuing from the back";
+    printDeque(deque);
+
+    /* 両端キューの長さを取得 */
+    int size = deque.size();
+    cout << "Length of the double-ended queue size = " << size << endl;
+
+    /* 両端キューが空かどうかを判定 */
+    bool empty = deque.empty();
+    cout << "Is the double-ended queue empty = " << empty << endl;
+
+    return 0;
+}