Unify talker_manager and listener_manager within InterfaceManager

[xtor]

Manager's add_talker and add_listener create their own InterfaceManager instances. We should have a single InterfaceManager instance that encapsulates the Tx and Rx resources needed on both directions.

For example, the following items should be considered as "per interface settings" that the unified InterfaceManager would need to control:

• VLAN interfaces
• Sockets
• Mappings (in some cases Rx and Tx mappings might differ, we would handle that once it occurs)
• ethtool channels configuration
• . . .