Prevent FABulous crash by checking for existing directory in do_place_and_rout_npnr

[IAmMarcelJung]

This checks if the specified directory exists and therefore prevents the CLI from crashing in if f"{name}.json" in os.listdir(f"{self.projectDir}/{path}"): if the specified directory does not exist.

I don't know why git marks so many lines as changed, since I only added a surrounding if and an additional else. Is this just do to the indention on python or is it my mistake? Sorry if the latter is the case and please tell me how an can correct it in that case.

[IAmMarcelJung]

Okay, thanks for your feedback!