Add support of sketchybar's configuration also as file

[vkravets]

I'm new in nix so don't sure if it will works ( , since don't know how to test it locally. Thus my applogize for this. I'll approciate If somebody point to doc or advise how I can check this.

It will be great if config also can be a path to config. It can be locallly created manually, or nix package, or home-manager