SNMP update 7: optimizing agent framework

Updated the #agent #framework in SNMP module. The #generic #SNMP #framework has been #optimized to use shorter #variable #names and removed the #length variable for many #multi-size #parameters. This makes uses of short & easier variable names. The memory size of many multi-size variables have been made static and length support has been removed reducing the memory requirement.

#SNMP update 7 ...
[commit 3a9909aa0941fc012cdd201877e514f3defef43d] (https://github.com/nes-repo/NES-Open-Switch/commit/3a9909aa0941fc012cdd201877e514f3defef43d)