Drop legacy Blender (<4.2) support from new addon

[kolibril13]

Blender 3.6 LTS support already ended, so I think it's a good time to also remove that legacy code for pre-blender 4.2 extensions:
https://www.blender.org/download/lts/3-6/

Here's the new Quickstart guide in action:

Screen.Recording.2026-02-19.at.14.38.32.mov

[Mateusz-Grzelinski]

Oh, wow, is the old style addon already legacy style? Wow, time flies fast. Fromage a quick look i think there is more code that handles legacy addon, but i will take deeper look some day

[kolibril13]

hi @Mateusz-Grzelinski, thanks for the reply!

Good point that there might be other legacy addon code, but I guess that could also be removed in another pr.

I have some further ideas to improve the quickstart guide, therefore the question:
Could we already merge this one, so that I can do some other tweaks on the quickstarts guide?

A few things I have in mind:

1. Make it more robust when already a README.md, .gitignore or LICENSE file is already present.
2. Also allow the quickstart guide to init the addon in a subfolder.
3. Maybe add some custom python wheels build scripts