ostbuild-qemu-pull-deploy: Cleanup leftovers

Remove development leftovers, no functional change.
build: Support more target trees

We need to the Maui installer to the build but we don't want to put
it to the runtime target, we want it to be available in the live tree
instead.  This means we need to support more targets.
build: Assume all components need to be rebuilt if --force-rebuild

When --force-rebuild argument is specified and no components are provided,
we assume that all components need a rebuild.