Add pyserial install to Wiki ?

[Doreapp]

While I was installing several times the repository, I noticed an error linked to serial python library.

It is easily solved using

sudo pip install pyserial

But it could be added to wiki, to avoid needing to debug this error
(And the install of pip too, for brand-new Ubuntu images)

Something like

sudo apt-get install python3-pip
sudo pip install pyserial

[svpcom]

Added in f46db37