apt-install: Pass --allow-remove-essential

This is needed in many cases when replacing packages from the target repos, e.g. replacing busybox-gzip with GNU gzip. I considered making this configurable, but it would have to be enabled for a large number of SDKs regardless, so the risk isn't significantly greater by having it always on.

Signed-off-by: Ryan Gonzalez ryan.gonzalez@collabora.com