Add 'textual diagnose' CLI command #1542
Description
We need a textual diagnose command which writes out some basic diagnostic information. We can ask for this in issue templates.
- Textual version
- Python version
- Path to Python executable
- OS
- Detect terminal, env vars TERM, COLORTERM, other terminal vars
- Output of rich.console.Console.options
The output may be colorized, but should be in an easy cut n pastable format.