Add installation instructions, links, documentation

[cirpene]

Adds accumulated information required to install the modpack for public use, without being locked behind opaque third-party services.

[Grokitach]

While I appreciate the gesture, the issue is that I need to maintain both which is double the work for me... I'll think about it.

[cirpene]

The most ideal scenario would be to have just some wiki to further facilitate collaboration, but it can be a considerable upfront investment time- and resource-wise.

But virtually anything is better for storing documentation and help materials than some walled-off garden that is not available in all countries, may require cell phone number to sign up (discord started to do this after some point) and has dubious TOS/Privacy policies one may have no inclination to agree with - required to just access the information - and public git repository comes close to the openness of wiki contributions, while imposing no legalistic/authentication requirements at all on read-only access.

[Grokitach]

I agree, and that's why everything will be stored on stalker-gamma.com at some point.