GMPLS update - 6: adding MPLS logical port update

Added stubs for logical #interface #status and #stacking handling in GMPLS module. This control the operations of logical interfaces of type #MPLS and #MPLS-Tunnel. Status handler will control the operations on an interface status change as in OPER UP/DOWN/TESTING etc ... On stacking of a higher layer entity similar operations are performed by stacking handler.

#GMPLS update 6 ...
[commit 91ead2c1b46bdb7569201b212411a00f78a5e308] (https://github.com/nes-repo/NES-Open-Switch/commit/91ead2c1b46bdb7569201b212411a00f78a5e308)