Enable port bindings

Set up nbetworking ports for the following use cases:

* bind the same port between host and container
* bind a specific host port to a different container port
* bind a random host port to a specific container port

Signed-off-by: baude <bbaude@redhat.com>

Closes: #214
Approved by: baude

cni/87-podman-bridge.conflist

@@ -0,0 +1,25 @@
+{
+    "cniVersion": "0.3.0",
+    "name": "podman",
+    "plugins": [
+      {
+        "type": "bridge",
+        "bridge": "cni0",
+        "isGateway": true,
+        "ipMasq": true,
+        "ipam": {
+            "type": "host-local",
+            "subnet": "10.88.0.0/16",
+            "routes": [
+                { "dst": "0.0.0.0/0" }
+            ]
+        }
+      },
+      {
+        "type": "portmap",
+        "capabilities": {
+          "portMappings": true
+        }
+      }
+    ]
+}