A bit of refactoring for generateChild

Mostly, this MR pulls the default child-naming logic out from the eight (!) different nearly-identical copies that exist currently and puts it in its own functions, one for surname and one for slave name.

It also pulls albinism-override generation into a shared function and cleans up a few other bits and pieces.

Tested on the Incubator side, assumed working on the Nursery side.