Prompt for name and email during initialization

[felipecrs]

To:

• Allow people to use my dotfiles without having to fork it, if they don't mind using my own preferences.
• Avoid the situation where someone installs my dotfiles without knowing that it would also configure Git to use my name and email. Reported by @diegogadens, thank you!

This PR also:

• Drop support for personal/work profiles. Now there isn't a distinction, and functionality everything will be as if it was personal. If you wonder why I'm dropping support for it, it's because now I maintain a dotfiles repository for my team in my company. And in the company machines, I use it instead.
• Revamp the README
• Bump minimum chezmoi version to 2.15.2 as it was with Go 1.18.1 (with support for continue and break keywords). Refs https://github.com/twpayne/chezmoi/discussions/1671.
• Add merge.autostash = true to .gitconfig, so that git pull works with less manual interventions.