granular verbose message suppression mechanics

Switch to using a macro invocation Verbos(n, s) in place of the
flags.verbose checks.

Provide the mechanics for individual suppression of any of the
existing messages that were considered verbose.

Mechanics only - this code update does not provide any means of
setting the suppression bits.

iflags.verbose = 0
is still a master suppression of all the verbose messages.

iflags.verbose = 1
turns on the verbose messages only for those whose suppression
bit is 0 (not set).

src/ball.c

@@ -55,7 +55,7 @@ ballfall(void)
             if (is_metallic(uarmh)) {
                 pline("Fortunately, you are wearing a hard helmet.");
                 dmg = 3;
-            } else if (flags.verbose)
+            } else if (Verbose(0, ballfall))
                 pline("%s does not protect you.", Yname2(uarmh));
         }
         losehp(Maybe_Half_Phys(dmg), "crunched in the head by an iron ball",