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>

src/finit.h

@@ -92,9 +92,9 @@ struct init_request {
 extern int    runlevel;
 extern int    cfglevel;
 extern int    prevlevel;
+extern int    debug;
 extern int    rescue;
 extern int    single;
-extern int    splash;
 extern char  *rcsd;
 extern char  *sdown;
 extern char  *network;