Automatically install nala instead of apt if missing?

[aminya]

setup-cpp currently supports using nala instead of apt to install the system packages on Ubuntu. Currently, it automatically uses nala if it is installed (previously or via --nala true).

But we can also enable the nala installation for all the calls to setup-cpp. In my opinion, nala works better and more reliably than apt.

https://gitlab.com/volian/nala/