(maint) Add "catalog_memory" benchmark to output heap and show mem info

This adds a benchmark "catalog_memory" that is running an empty catalog
(one call to log). A baseline sample of memory is taken at first run,
and at last. A diff of bound objects is produced. Two heap dumps in json
formats "diff.json", and "heap.json" are produced. The diff contains the
dump of each bound object, and the heap a dump of all objects.

The benchmark also prints basic information about memory.