Each symbol unit in eeschema has a unique identifier. But we don't have
a unique identifier for the entire symbol. So changing which symbol
instance was unit A (our default base for matching), changed the UUID
that we were using to match the footprints.
This commit adds all UUIDs to the netlist, allowing us to match symbol
to footprint without worrying about which unit is referenced.
This still does not handle changing different units on different sheets.
Fixes https://gitlab.com/kicad/code/kicad/issues/7604
Seth Hillbrand
Marek Roszko