Add Rich-based SVG Rendering for program-output

[mgaitan]

This PR introduces the ability to render program output using Rich in an SVG format. When Rich mode is active, the output is styled with colors and formatting, resulting in a nicer visual appearance compared to a standard literal block.

How It Works

• Global Enable: Set programoutput_force_rich = True in your conf.py to force Rich for all directives.
• Per Directive: Use the :rich: option on a .. program-output:: directive.
• Width and Colors: Rich respects environment variables like COLUMNS (to set the console width) and FORCE_COLOR (to force ANSI colors).

Example Usage

.. command-output:: python -m rich
   :rich:

PS: in addition I upgraded pyproject.toml and removed setup.py

[jamadden]

I can't review this PR as is, it contains many unnecessary changes (removal of setup.py, formatting and commenting changes, etc, etc, etc). Please provide a PR with only the necessary changes.

[mgaitan]

I apologize for the messy implementation. I truly believe that every change adds value. Ideally, I would have separated these into different pull requests, but I simply don't have the time right now.

I completely understand if you decide not to merge this, but perhaps others might find the feature useful.

[mgaitan]

moved to https://github.com/mgaitan/richterm