MEDIUM: server: switch conf.name to cebis_tree

MEDIUM: server: switch conf.name to cebis_tree

This is used to index the server name and it contains a copy of the
pointer to the server's name in <id>. Changing that for a ceb_node placed
just before <id> saves 32 bytes to the struct server, which remains 3968
bytes large due to alignment. The proxy struct shrinks by 8 bytes to 3144.

It's worth noting that the current way duplicate names are handled remains
based on the previous mechanism where dups were permitted. Ideally we
should now reject them during insertion and use unique key trees instead.