Remove duplication of create_aliased_image_handle implementations
requested to merge aron.virginas-tar/vulkan-wsi-layer:refactor_create_aliased_image_handle_4 into master
This change refactors the create_aliased_image_handle() method in order to reduce code duplication. Previously there were two nearly identical implementations for the Headless and Wayland backends. These are being replaced with a single implementation, which now resides in swapchain_base.
The refactoring also alters the way image creation parameters are being stored in the swapchain, in order to maintain a common interface across the two implementations.