dir names and pnames of custom nodes should be mechanically derived from their repo names

[adrian-gierakowski]

currently some of the names follow a pattern, but we also have a lot of arbitrary ones
if we want to automate addition of new custom nodes we should have a function which would take name of the custom-nodes gh repo (all seem to be hosted on gh) and output consistent name which could be used for nodes dir and pname

my proposal would be to convert repo name to kebab case by:

1. replacing _ with -
2. splitting camelCase into segments => camel-case

some other points for bike shedding:

1. remove comfyui prefix (currently added to all nodes). It would make sense if we wanted to include all these node at the top level of nixpkgs, but since they are nested in a sub-set, it seems to serve no purpose
2. kind orthogonal but since we would be introducing breaking changes (we can provide aliases for a while with deprecation warnings), we could also reorganise the scripture of the comfyui overlay. For example, we could have:

comfyui = {
  comfyui = THE_PACKAGE
  nodes = ...
  lib = ...
  ...
}