Improve conversion of bytes to human readable string

Fixes issues like showing 0 MiB when the value is just slightly less then 1 MiB.

pglablib/utils/HumanReadableBytes.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <string>
+
+std::string HumanReadableBytes(uint64_t bytes);