「OpenRTM-aistとは？」の更新

[h8892-inaba]

link to #293

Drupal更新に伴い、以下のGitHubを更新しました。

• https://openrtm.org/openrtm/ja/doc/aboutopenrtm

  • /documents/01_aboutopenrtm/01_about_openrtm_ja.txt

• [x] Did you check grammar? (ex. https://www.grammarly.com/, https://www.kiji-check.com/)

• [x] Did you check pukiwiki grammar?

• [x] Did you check Japanese-English consistency?