ufw is called before it was installed

[MoezLog]

In the middle of the installation, I received an error that ufw is non existant. I stopped the script and did manually a sudo apt install ufw then started again. Not all servers got a UFW installed by default.

[alokemajumder]

Fixed in commit bbcb332. The script now checks if UFW is installed before configuration and installs it automatically if missing.