patches: ubuntu/genimg — move guest DNS override to end of script

patches: ubuntu/genimg — fix guest DNS (SLIRP proxy) and -p1 hint

patches: ubuntu/genimg — correct context lines for the network hunk

The previous version had stale context (EOF / fi / DHCP=yes) that didn't
match the actual recipe. Replace with the real surrounding lines (resolv.conf
nameservers above, Address=10.0.2.15/24 below) so `patch -p0` applies
cleanly on a fresh apk recipe tree.

patches: ubuntu/genimg — widen systemd-networkd match to Name=en*

Third hunk in the ubuntu/genimg patch. Upstream only writes
25-ens3.network matching Name=ens3, but on modern noble + virtio the
kernel names the interface enp0s3 instead, so DHCP never starts and
the build-worker times out in 'Waiting for guest to settle'. Rename
the file to 25-ethernet.network and broaden [Match] Name= to en*.

patches: track ubuntu/genimg nbd-settle and chroot-chown fixes

Two-bug patch against builds.sr.ht-images ubuntu/genimg, applied
out-of-band on work.lab.local but not yet upstreamed to sr.ht-dev.