Update Prerequisites for Different Platforms

[MichaelLettrich]

I reviewed the prerequisites for installing ALICE O2 on the different platforms. Using containers I verified that the installation of the prerequisites works and that aliDoctor does not complain on all of the listed platforms and OS versions.

Asking for a review

[mpuccio]

Please restore the automatic build checks

[ktf]

For the record, once we merge alisw/alidist#2034 this can be simplified further, because the system installation of python modules becomes a mere detail and we can pick up whatever people have in their environment and add on top our prerequisites. I think this also obsoletes the requirement to have pip3 preinstalled, as one can create a venv without it which will then install the latest pip3 version inside.

[mconcas]

Hi @MichaelLettrich , thanks for you PR.
Many parts were indeed obsolete or, arguably, too verbose.
Thanks for your contribution.
One comment aside:
The tone of the guide used to be more "handy" for newcomers, since it was tailored to be adopted in analysis tutorials.
With these changes it would be now more concise indeed.
I understand that the scope of this page is now asked to cover a broader public that perhaps requires less explanations and more direct shell commands.

To me this can be merged, provided the capitalisation of second words in a sentence is removed, :)

[MichaelLettrich]

@mconcas - I understand that there are different schools on how good documentation should look like. Here is my take:
Documentation should be "everything should be made as simple as possible but nor simpler ", i.e. :

• Give the user clear instructions what to do, especially those with little domain knowledge
• Use concise, uncomplicated statements
• Only introduce concepts that are strictly necessary to understand the topic

Thus: Focus on beginners who don't want a lecture about internals of AliBuild and their OS but to write analysis tasks. Domain experts/ long term users will do whatever they think is correct anyway or simply copy& paste the commands.

Again, I think Dario did a great job setting up the documentation but a lot of things are outdated or were simplified .

[mpuccio]

I actually think that context helps in understanding and troubleshooting (and as you said, there are different schools of thinking about documentation, so don't consider your points as universally taken :) ). Remember: this is the analysis tutorial documentation and it is meant to teach people not only how to do things, but also how the various pieces work.
However, as I said already, we welcome your contribution and we are very pleased that that the building instructions are in the hands of the offline again.
I would now merge this. Thanks a lot!!