add installation instructions for gdal with pixi.sh

[gregorywaynepower]

Feature description

I would like installation instructions via pixi.sh to be included in the documentation. It's a tool made by prefix.dev that functions similarly to conda/mamba . It allows users to install gdal within a project, or as a globally available tool.

Additional context

No response

[rouault]

I would like installation instructions via pixi.sh to be included in the documentation

by whom? If you're volunteering, why not. As far as I'm concerned, I had never heard about it before

[gregorywaynepower]

Yeah, I'm working on a PR for this request. Sorry if the issue sounded a tad demanding. 😅