Drop confusing splash cmdline and --enable-progress configure option

This patch reverts back to the progress/status behavior of Finit < v3.0
because this is what most users expect, including the maintainer.  The
resulting code and configure script is a lot simpler to understand and
maintain:

- No more --enable-progress or --enable-progress-classic configure
  flags.  Instead a progress_style variable in helpers.c that can
  be changed at compile time for those that really need it.
- No more 'splash' kernel commnand line option.  This turned out to
  be *very* confusing to many users who believed it was some sort of
  graphical splash screen à la Plymouth.

Also, when Finit debug is enabled we now have a global 'debug' flag
which now alo controls if klogctl() should be called to prevent the
kernel logs to the console or not.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

plugins/hotplug.c

@@ -74,7 +74,7 @@ static void setup(void *arg)
 		path = which("mdev");
 		if (path) {
 			/* Embedded Linux systems usually have BusyBox mdev */
-			if (log_is_debug())
+			if (debug)
 				touch("/dev/mdev.log");
 
 			snprintf(cmd, sizeof(cmd), "%s -s", path);