Write prerequisites section for new packaging tutorials

(For more information about this issue, please see #194).

We need a short section to follow the tutorial introduction (see #195) that makes sure the user has a working Python environment. This should line up with what's in Install pip, setuptools, and wheel, but using a more step-by-step approach (rather than the more self-directed approach of the other section). Additionally, it would be nice to have a step (or steps) that help readers verify that the tools are working.

When opening pull requests for this issue, please submit to the develop branch. If you have questions that concern contributing more generally, please use issue #194. Otherwise, feel free to comment with questions or feedback. Thanks!

#195で参照されているチュートリアルの導入部、#194のより広範なコントリビューションガイダンス、およびリンク先の「Install pip, setuptools, and wheel」の資料を確認してください。動作するPython環境の前提条件について、検証手順を含む短い手順形式のセクションを追加し、pull requestをdevelopブランチに提出してください。