doxygen from home:ila.embsys project

For xUbuntu 22.04 run the following:

Keep in mind that the owner of the key may distribute updates, packages and repositories that your system will trust (more information).

echo 'deb http://download.opensuse.org/repositories/home:/ila.embsys/xUbuntu_22.04/ /' | sudo tee /etc/apt/sources.list.d/home:ila.embsys.list
curl -fsSL https://download.opensuse.org/repositories/home:ila.embsys/xUbuntu_22.04/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/home_ila.embsys.gpg > /dev/null
sudo apt update
sudo apt install doxygen