(ichr, pchr, dchr, intrchr): Move initializer to new builtin config

files item.config, product.config, sect.config, infra.config.
(empfile): Declare the new config files.  Reorder table entries so
that read_builtin_tables() reads the config files in the right order.

(bigcity_dchr, opt_BIG_CITY, init_dchr): Remove.  Deities can edit
sect.config instead.

src/lib/global/options.c

@@ -37,7 +37,6 @@
 #include "optlist.h"
 
 int opt_ALL_BLEED = 1;
-int opt_BIG_CITY = 0;
 int opt_BLITZ = 1;
 int opt_BRIDGETOWERS = 1;
 int opt_DEFENSE_INFRA = 0;