Split out pretty-print.c and move pager.c and main-func.h to shared/

This is high-level functionality, and fits better in shared/ (which is for
our executables), than in basic/ (which is also for libraries).

src/machine-id-setup/machine-id-setup-main.c

@@ -11,7 +11,7 @@
 #include "machine-id-setup.h"
 #include "main-func.h"
 #include "path-util.h"
-#include "terminal-util.h"
+#include "pretty-print.h"
 #include "util.h"
 
 static char *arg_root = NULL;