[project] Generate syscalls from new interface DSL

This change adds a new interface DSL for specifying objects (with
methods) and interfaces (that expose objects, and optionally have their
own methods).

Significant changes:

- Add the new scripts/definitions Python module to parse the DSL
- Add the new definitions directory containing DSL definition files
- Use cog to generate syscall-related code in kernel and libj6
- Unify ordering of pointer + length pairs in interfaces

src/user/srv.init/modules.cpp

@@ -70,7 +70,7 @@ modules::load_modules(uintptr_t address, j6_handle_t system, j6_handle_t self)
 
         char message[100];
         sprintf(message, "srv.init found %d modules from page at 0x%lx", page->count, address);
-        j6_system_log(message);
+        j6_log(message);
 
         if (!first)
             first = page->modules;