of_lldp should create flows per interface instead of just one generic flow

[viniarck]

• of_lldp should create flows per interface instead of just one generic flow

Also:

• Fix openapi lldp spec receive -> send and receive text
• Should the default behavior should be dropped?
• of_lldp should follow kytosd -E` kytos flag behavior
• Adapt end to end flows counter when implementing this (related to coloring issue)

[viniarck]

In the future, it's worth reassessing the default expected discovery behavior, because even if it could try to follow the -E option, for logical interfaces like bfd it could lead in being enabled on interfaces where it might not expected. I encountered this case when exploring bfd on NoviFlow switches. This still needs more discussion and whether or not this should only be explicitly enabled on interfaces, although for plug and play it's great to have the topology discovery.