CORD-339 Network config host provider

* Implement new application org.onosproject.netcfghost
* Implement BasicHostConfig to include IP and location information
    - Update network-cfg.json to add host config example
    - Add network-cfg-2x2-leaf-spine.json for 2x2 leaf-spine network in SegmentRouting
* Update Segment Rounting
    - Punt ARP packets
      (which is done by HostLocationProvider previously)
    - Check existing hosts when device connected or configured

Change-Id: I03986ddc8203d740b5bf26903e3dbf866d4d4600
diff --git a/providers/pom.xml b/providers/pom.xml
index 32890b9..8bf0285 100644
--- a/providers/pom.xml
+++ b/providers/pom.xml
@@ -35,6 +35,7 @@
         <module>openflow</module>
         <module>lldp</module>
         <module>host</module>
+        <module>netcfghost</module>
         <module>netconf</module>
         <module>null</module>
         <module>pcep</module>