This introduces the native resource type to manipulate qemu.conf, so
that we can define the resources in the same way for all libvirt
config files.
This also updates all libvirt config resource types to convert boolean
values automatically, because libvirt does not support raw boolean
values and the values should be converted to 1/0.
Change-Id: I562d19299e0377e02f2587f5ef36d35069b5a5cd