Revert "Makefile.template-aur: use own pacman wrapper (utils/pacman.sh) to allow installations with conflicts (albeit not unattended)."

This reverts commit 6252195f970b52258366dd6ce2f1a61f57ae796f.
Makefile.template-aur: use 'yes y' to automatically agree with removing conflicted packages.

This is a "proper" fix for the issue of last reverted commit.