Now that the inline uniform rewrite has landed, this is relatively straightforward to implement. We just need to tweak the descriptor writing slightly to match the API of
CmdGetDescriptorEXT, pull out the part where we actually emit the descriptor sets, and implement
CmdSetDescriptorBufferOffsetsEXT very similarly to
CmdBindDescriptorSets. Embedded samplers are handled by creating the descriptor set up-front when the layout is created and just binding it, although we could improve it later by suballocating these if necessary.