basic: Move assertion specific functions to assert-util.h

Various functions in log.h are only used by asserts, and there's
enough assertion related stuff in macro.h to justify a separate header
which also makes it easier to avoid circular dependencies.

Let's introduce assert-util.h and an accompanying fundamental header
and move all the assertion related stuff over there. PROJECT_FILE is
moved over to macro.h.

src/basic/alloc-util.h

@@ -7,6 +7,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "assert-util.h"
 #include "macro.h"
 
 #if HAS_FEATURE_MEMORY_SANITIZER