Improved installation script for arch based distros

[mroetsc]

I have added the --needed flag to the pacman install to not reinstall any dependencies that are already present on the system (docs). I also added the dependencies that are installed on other systems but where missing on the pacman install.

The script also used yay exclusively, although there are people that use paru (GitHub) as a helper for the AUR, where python3.9 is installed from. The script now detects whether the user has yay or paru installed, when both are not found, it installs yay.