Add per-server /64 route generation
Add per-server /64 route generation

Summary:
This generates /64 static routes in RSW agent config, one per
server. Per alexey we generate 384 entries, which currently has a
caveat - the agent tries to resolve every next-hop proactively. This does
not to affect CPU util much, though, only pollutes the log file.

The config generation is done based on information from FBNet (service prefix).
This diff does not modify coop template, but instead adds new fields in dictionary
explicitly. It might be nicer to add staticRoutes to the template, as this would
allow to address them as attributes.

This also adds static aggregate route to bgpD config.

Reviewed By: aeckert

Differential Revision: D3245667

fbshipit-source-id: 7af6720bf744acd10b2765f977a2c29beddd2ccc

peterlei/fboss,peterlei/fboss,peterlei/fboss,peterlei/fboss