qa/dnsmasq: use managed dnsmasq instead of editing resolv.conf

this task was manually editing /etc/resolv.conf to configure dns names.
on ubuntu 24, these changes were getting clobbered by NetworkManager or
systemd service restarts

instead, manage dnsmasq depending on host distro. rpm-based distros use
NetworkManager's dnsmasq plugin, while deb-based distros use
systemd-resolved to point at the local dnsmasq

Fixes: https://tracker.ceph.com/issues/76961

Signed-off-by: Casey Bodley <cbodley@redhat.com>