Move GDS metadata into its own model

[thomasdorch]

Related to #2623.

Creates a new model for the metadata intended to be written to the GDS file.

[joamatab]

Hi Thomas,

i think this won't be supported by kfactory, and it's a bit confusing to have two separate Objects for metadata

something you can do is

c = gf.Component()
c.my_info = dict(key=value, message='whatever')

def save_gds_with_custom_info(c, gdspath)
    c.write(gds)
    json.dumps(c.my_info)

What do you think?

@sebastian-goeldi

[sebastian-goeldi]

I think Thomas's request is reasonable. There should be a place where you can store info why is not kfactory/klayout serializable. I just haven't come across a use case for this. Hence kfactory doesn't have it.

If you are already making an exception for schematic, it might be time to either split info or split it in a smart way. I agree though, it's not good to have a generic dict which has some fields with dedicated type restrictions (be it schematic or any other exception).

If you want something like that, I think a protocol or similar would be in order to describe the static attributes. This makes info a lot more complex though.