CLI support to query memory usage for a specific map

[saxena-anurag]

This issue is to add support in CLIs to be able to query current memory usage for a given map ID.

The reported value should include the memory allocated for actual key / value, plus the extra memory allocated by ebpfcore for book keeping (e.g. buckets allocated for hash table, etc.).

[shankarseal]

@saxena-anurag please investigate the feasibility of using bpftool to have a x-plat solution.

[vpidatala94]

@saxena-anurag - if we are also interested in capturing "extra memory/booking memory" - memory occupied by ebpcore, my question is it feasible to do so for a particular map ID as we are geneally allocating memory from a pool tag. Total memory consumed per pool tag (all maps combined) seems more plausible or we just capture the memory consumption of a ebpf map (key_size + value_size) * total_entries

[vpidatala94]

issued pushed to backlog based on discussion the original request was made to help with benchmarking in SC project which we are now interesting capturing the programatic way