[ docs ] add ubuntu installation procedure
[ docs ] add ubuntu installation procedure

debian installation procedure goes well also for ubuntu

insomnia-lab/libreant,insomnia-lab/libreant,ael-code/libreant,g3-3k/libreant,g3-3k/libreant,insomnia-lab/libreant,leophys/libreant,insomnia-lab/libreant,leophys/libreant,ael-code/libreant,ael-code/libreant,g3-3k/libreant,leophys/libreant,leophys/libreant,ael-code/libreant,g3-3k/libreant