LAG upgrade - 9: member port API update

Updated #external #create / #remove #API for #member #ports in LAG module. Removed references to augmented data-structures from these routines. The external #create API creates the member port configuration entry and it's #associated #data-structures like port #statistics and #debugging parameters. The #custom member port parameter entries and #extended configuration entries are also #instantiated along with the create operation. On the #remove call these #dependent #structures are #removed first followed by the member port itself.

#LAG update 17 ...
[commit 6abe1d466fa297b915ef0a4591b8bc60e77eb3cc] (https://github.com/nes-repo/NES-Open-Switch/commit/6abe1d466fa297b915ef0a4591b8bc60e77eb3cc)