Move Package Creation wiki out of github

[LightFelicis]

Context:
We have a wiki on github about package creation, however it's nearly impossible to find by the average user. It's a great source of knowledge and we should increase its visibility.

Idea:
Move package creation wiki (or add a link to github wiki) to "Add task" section, so if any teacher wants to upload the package they can easily access the docs.

Why it's important:
It's impossible to guess the package format from sio platform and reading the package parsing code is not a way. We put some effort into package creation tutorials (paczkomat.dasie.mimuw.edu.pl is a POC for this) and it received very warm welcome from teachers.

[LightFelicis]

@twalen Hi I think this could be a good starter task for TAG group, could you please triage this issue? Tentatively assigning to you :) Thank you!

[DietPawel]

On behalf of my team I declare support for this idea. We can help with technical side of creating a wiki.