Outdated dependencies building instructions

[MakisH]

This page needs to be updated to 2024 and preCICE v3: https://precice.org/installation-source-dependencies.html

[uekerman]

Some things that are outdated (since I just stumbled over them):

• Ubuntu 20.04 (and older): boost is no longer available through aptitude
• boost: we now require 1.74