this completes the splitup of server.c.

this completes the splitup of server.c.

the splitup was done with an axe, not a scalpel, so there are some
rough edges. I mostly wanted to get the general form right with fine
tuning of what goes where to come later. Still, this is better than
what we had before where server.c was a general repository for
anything that didn't fit elsewhere.
(This used to be commit a6d194886a4a5f7507fa37289ff96c1be56f14a6)