Support pipewire dmabuf video streams with modifiers

Modern graphics cards have this feature that it makes sense to support where buffers are set up using certain modifiers to be able to store the data in convenient ways.

Both producer and consumers need to support this, therefore the logic gets rather complex. This is an attempt to implement this.

It will stop being a draft when

• It works on devices with dmabuf but not modifiers (working)
• It works on devices that support modifiers and uses the modifiers
• It works on nvidia, where I'll need help to test because I don't have the hardware and it's not precisely cheap. No need yet because it needs the previous point.