Implement host probing retry with major refactoring

- Implement probe retry
- Switch to typical core/provider design pattern for HostProbingService
  and as a result decoupling the dependency between SR and HostLocationProvider

Change-Id: I33a15af580677ea376b421ac3e26f9821dcca844
diff --git a/modules.defs b/modules.defs
index 3c96b1a..dabd5f9 100644
--- a/modules.defs
+++ b/modules.defs
@@ -126,6 +126,7 @@
     '//providers/bgp:onos-providers-bgp-oar',
     '//providers/bgpcep:onos-providers-bgpcep-oar',
     '//providers/host:onos-providers-host-oar',
+    '//providers/hostprobing:onos-providers-hostprobing-oar',
     '//providers/lldp:onos-providers-lldp-oar',
     '//providers/netcfghost:onos-providers-netcfghost-oar',
     '//providers/netcfglinks:onos-providers-netcfglinks-oar',