Inject metadata properties automatically to non-admin images

The operator provides public images to the users and users can also add their own images in glance and use these images to launch VMs. As an operator, all images provided by an operator should be launched on a specific set of compute nodes whereas images that are created by non-admin users should be launched on other set of compute nodes. The decision to launch VMs on certain compute
nodes will be decided based on image metadata. When an operator will create images, they can specify certain image metadata which will be used by placement api or scheduler service to decide where the vm should be launched but if user creates image, there is no way user will know what image metadata properties to set and hence in the present placement api and scheduler logic, it is possible to launch a VM on any compute nodes. This is a big problem.