Refactor, move registration of static services to conf_init()

All services registered in the system rely on conf_init() having been
set up properly, e.g., global_rlimit.  Having conf_init() be responsible
also for registering static services is only logical, and also helps us
clean up main() a bit.

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

src/api.c

@@ -50,7 +50,6 @@
 #include "sig.h"
 #include "util.h"
 
-extern svc_t *wdog;
 static uev_t api_watcher;
 
 static int call(int (*action)(svc_t *, void *), char *buf, size_t len)