netboot: Deploy drop-in for systemd-network-generator.service

netboot: Deploy drop-in for systemd-network-generator.service

Disable the systemd-network-generator with a drop-in when nbd.server is set
on the kernel cmdline.

Also extend options passed to connmand with known renamed interface names.

Bug-AGL: SPEC-5196
Change-Id: Ia81096262c407f48e801ec4858c4043398b67baa
Signed-off-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/30056
Tested-by: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account
ci-image-build: Jenkins Job builder account