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

lib/ws.c

@@ -1426,7 +1426,7 @@ CURLcode Curl_ws_accept(struct Curl_easy *data,
       k->keepon |= KEEP_SEND;
     }
 
-    /* And pass any additional data to the writers */
+    /* Then pass any additional data to the writers */
     if(nread) {
       result = Curl_client_write(data, CLIENTWRITE_BODY, mem, nread);
       if(result)