Enhance documentation for pipx

[briancohan]

Create a wiki page or update README to provide more guidance on installing and setting up pipx. Documentation should be minimal but point to appropriate pages on the pipx website.

Minimum topics needed to be covered:

• Installing Python
• Installing pip (if it's not automatically installed)
• Enabling virtual environments if you can't create a venv
• pipx ensurepath (and reloading terminal)