Provide a map between all devices and their driver names

- Introduce a new Java API in DriverService
- Implement a new CLI command device-drivers that dumps all devices and their driver names or a driver name of a device
- Include this CLI command as part of onos-diags

Change-Id: I978690e6af6c00dbfc09259b50449779b1167754
(cherry picked from commit dfaf4622e00256a8063ec4f12765381f7290a476)
diff --git a/tools/package/runtime/bin/onos-diagnostics b/tools/package/runtime/bin/onos-diagnostics
index 9a085ee..c2e9f77 100755
--- a/tools/package/runtime/bin/onos-diagnostics
+++ b/tools/package/runtime/bin/onos-diagnostics
@@ -70,6 +70,7 @@
     "cfg get"
 
     "devices"
+    "device-drivers"
     "links"
     "hosts"
     "interfaces"