Everywhere: Add serenity_dev_{makedev,major,minor}

Add them in `<Kernel/API/Device.h>` and use these to provides
`{makedev,major,minor}` in `<sys/sysmacros.h>`. It aims to be more in
line with other Unix implementations and avoid code duplication in user
land.

Userland/Utilities/stat.cpp

@@ -12,6 +12,7 @@
 #include <LibMain/Main.h>
 #include <grp.h>
 #include <pwd.h>
+#include <sys/sysmacros.h>
 #include <time.h>
 
 static ErrorOr<int> stat(StringView file, bool should_follow_links)