Possibility to anonymize yourself

## Is your feature request related to a problem? Please describe

On signup, it would be useful if a user could select whether or not they want to show their personal information to other users.

If they chose this option, their profile picture would be redacted and their name randomly generated.

This "Be anonymous" would be a one time choice, you cannot revert back/opt-in after your account is created.

## Describe the solution you'd like

This would allow for users to still participate in discussions.

## Describe alternatives you've considered

A clear and concise description of any alternative solutions or features you've considered.

issueにはファイルやテストが指定されていません。まず、Go、React、TypeScriptアプリケーションのサインアップとプロフィールのエントリポイントを追跡し、一度だけ行う匿名化の選択、プロフィール画像の墨消し、生成される名前、不可逆的な動作を定義してから、匿名ユーザーが引き続きディスカッションに参加できることを確認してください。

索引モデルが issue の本文から書いたものです。