[Dev] ParabolaWiki installation guide

[anarcobuda]

i've been doing some work on our wiki, mainly the installation guide,
to improve readability and to update some information

we ascribe to the 'arch way', since we use basically an arch-based
system, and there's no reason why our installation guide should be
different than the archwiki's one.

however, we also openly provide an openrc version of parabola, and that
means we can't pragmatically copy and paste archwiki's installation
guide, since it'd be only useful for systemd users.

in that sense, i'm asking for opinions on how to organize this and i
came up with two possibilities so far

1. do a step-by-step guide for openrc and another for systemd
this would mean there would be a main page for pre-installation and two
pages for installation, one for openrc and another for systemd.
this seems to be the easiest to do, since it only requires two extra
pages

2. do a step-by-step guide for both, in one page with the help of links
this would mean one page that would branch out on other pages
for instance, a page section that says "configure your network" and
it'd link to another page that details how to configure your network
for openrc and systemd in different sections
this seems more work-consuming, but it'd be neater

what do you think?