Add web page listing OHW22 projects

We haven't created a page listing all the projects that were carried out in OHW22. For example, a page like this one from OHW21, which lists each project, the repo link, Youtube recording link, and a brief project summary.

At the root level of our OHW Google Drive there's a Google Sheet document ("ohw_proj_summary") that lists projects from each year, including OHW22. @leewujung was the last one to edit it. I assume that will be our starting point for the OHW22 projects page.

https://oceanhackweek.org/about/pasthackweeks.html is a single go-to page to all the OHW events. Once we have the OHW22 projects page, let's add an entry and link in that Past OHW Events page.

OHW21 のプロジェクト一覧ページをレイアウトの参考にし、Google Sheet の「ohw_proj_summary」をデータソースとして使用します。サイトの既存のページ構成と about/pasthackweeks.html を調査してください。OHW22 ページに各プロジェクトのリポジトリ、YouTube 録画、概要が一覧表示され、Past OHW Events ページからそのページにリンクされていれば完了です。