waku2: use rendezvous

[richard-ramos]

See: waku-org/go-waku#488

To use this functionality within status-go, when a waku node is instantiated the following option must be passed:

node.WithRendezvous(rendezvousNodes)

with rendezvousNodes being a slice of multiaddr.Multiaddr. I imagine these could be obtained from here: https://github.com/status-im/status-go/blob/develop/wakuv2/waku.go#L490-L511 which uses dns discovery to obtain the list of peers from the fleet (nwaku should support rendezvous first); or, the list of multiaddresses could be hardcoded, and use go-waku nodes.

cc: @cammellos