lib, zebra: Add ability to notify to Routing Protocols Success/Failure

lib, zebra: Add ability to notify to Routing Protocols Success/Failure

Provide ZAPI code that can pass to an upper level protocol
what happened to it's route on install.

There are these notifications:
1) ZAPI_ROUTE_FAIL_INSTALL - The route attempted to be
   installed did not work.
2) ZAPI_ROUTE_BETTER_ADMIN_WON - A route that was installed
   has become un-installed due to another routing protocol
   installing a better admin distance
3) ZAPI_ROUTE_INSTALLED - The route specified has been installed

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>