IF update - 7: agent cleanup

Added various #correction s in IF module. Optimized numerous member fields to #shrink #variable #size and #reduce #memory #utilization. Added #new #indexing for interface entries and stubs for interface external API. Upgraded interface configuration entries in order to remove the augmented data-structures.

#IF update 7 ...
[commit ad6b80ac0bbf8f925f1a9a5bf8bde38994915705] (https://github.com/nes-repo/NES-Open-Switch/commit/ad6b80ac0bbf8f925f1a9a5bf8bde38994915705)