torsvc: Added new module to house Tor functions

This commit adds a new module named 'torsvc' which houses all Tor
functionality in an attempt to isolate it and make it reusable in
other projecs. Some additional tweaks were made to config.go and
to the bootstrapper.

server.go

@@ -605,7 +605,8 @@ func initNetworkBootstrappers(s *server) ([]discovery.NetworkPeerBootstrapper, e
 
 			dnsBootStrapper, err := discovery.NewDNSSeedBootstrapper(
 				dnsSeeds,
-				[]interface{}{lndLookup, lndLookupSRV},
+				lndLookup,
+				lndLookupSRV,
 			)
 			if err != nil {
 				return nil, err