Add AUR helper

Add AUR helper
```bash
sudo pacman -S --needed base-devel
git clone https://aur.archlinux.org/paru.git
cd paru
makepkg -si
paru -Syu paru-bin
```

And optimize its config
```bash
# /etc/paru.conf
Devel
#RemoveMake
CleanAfter
NewsOnUpgrade
SkipReview
```