docs: add repository anatomy to contribute-to-precice #838

[dhanushsaimudari]

add repository anatomy to contribute-to-precice resolving issue #838

for better understanding for new contributor who want understand the House Analogy of website repo

[Aayushman-nvm]

Hi @dhanushsaimudari
Thanks for the PR, but I see few mistakes... did you fully rely on some tool or did you actually go through the repo?

[MakisH]

I removed some files in #854, this is (at least partly) why the content here looks a bit different.

But definitely, some sections are "fluffier" than they need to be.

[Aayushman-nvm]

@MakisH thanks for the reference, I understand now

But still... for an instance look at assets/
It doesnt have css files