badwords: rework exceptions, fix many of them

Also:
- support per-directory and per-upper-directory whitelist entries.
- convert badlist input grep tweak into the above format.
  (except for 'And' which had just a few hits.)
- fix many code exceptions, but do not enforce.
  (there also remain about 350 'will' uses in lib)
- fix badwords in example code, drop exceptions.
- badwords-all: convert to Perl.
  To make it usable from CMake.
- FAQ: reword to not use 'will'. Drop exception.

Closes #20886

docs/examples/block_ip.c

@@ -127,7 +127,7 @@ static struct ip *ip_list_append(struct ip *list, const char *data)
     return NULL;
   }
 
-  /* determine the number of bits that this IP will match against */
+  /* determine the number of bits that this IP matches against */
   cidr = strchr(ip->str, '/');
   if(cidr) {
     ip->maskbits = atoi(cidr + 1);