Disable host learning feature.

This patch gives us the ability to disable
host learning in certain ports via the ports
configuration.

We have the following cases :
        - Discover a host with no learning configuration, this
          results to learned host (missing config assumes learning is on)
        - Discover a host with learning configuration set to false,
          do not learn that host.
        - Update the learning configuration of a CP to false. Then,
          fetch all host at that location, if these hosts are not
          configured statically at this location, remove them

Change-Id: I2a05ce5f9a890bb4049fd7856f95d78f467e3330
diff --git a/core/api/src/test/resources/host-learning-config.json b/core/api/src/test/resources/host-learning-config.json
new file mode 100644
index 0000000..4ff6266
--- /dev/null
+++ b/core/api/src/test/resources/host-learning-config.json
@@ -0,0 +1,3 @@
+{
+  "enabled" : true
+}
\ No newline at end of file