[ONE-22] Solve overwriting default route problems and fwd native

[vvalderrv]

Solve overwriting default route problems and fwd native

• solve contention between LISP default and CLI configured default
• ensure that non EID packets that reach encap are forwarded to the right interface (might not be a problem if we branch off at ip-input or at interface output node features)
• ensure that encapsulated packets are not returned to ip-lookup. If FIB has only a default route (competing with lisp default) we have a loop
• allow statics with forward native that use previous default (or more specific route)