Refactor connectivity intent creation to use builders

- Each connectivity intent now has only one constructor
- Intent constructors are now private for leaf classes and
  protected for classes that can be derived from
- Each intent class has a Builder class that accumulates
  parameters for intent creation
- Each intent class has a public static builder() method
  to create a builder
- Each Builder class has a build() method to create the
  intent from the accumulated parameters
- Added keys to a few intent types that were missing them
- Tightened up usage of checkNotNull(), taking advantage of
  the return value to save some lines of code
- Modified callers to use the builders instead of directly
  calling the constructors

Change-Id: I713185d5ecbadbf51f87ef7f68fec41102106c78
diff --git a/apps/sdnip/src/test/java/org/onosproject/sdnip/IntentSyncTest.java b/apps/sdnip/src/test/java/org/onosproject/sdnip/IntentSyncTest.java
index 9f29c1b..7625af6 100644
--- a/apps/sdnip/src/test/java/org/onosproject/sdnip/IntentSyncTest.java
+++ b/apps/sdnip/src/test/java/org/onosproject/sdnip/IntentSyncTest.java
@@ -233,9 +233,13 @@
         ingressPoints.add(SW4_ETH1);
 
         MultiPointToSinglePointIntent intent =
-                new MultiPointToSinglePointIntent(APPID,
-                                                  selectorBuilder.build(), treatmentBuilder.build(),
-                                                  ingressPoints, SW1_ETH1);
+                MultiPointToSinglePointIntent.builder()
+                        .appId(APPID)
+                        .selector(selectorBuilder.build())
+                        .treatment(treatmentBuilder.build())
+                        .ingressPoints(ingressPoints)
+                        .egressPoint(SW1_ETH1)
+                        .build();
 
         // Setup the expected intents
         intentService.submit(eqExceptId(intent));
@@ -291,9 +295,13 @@
         ingressPoints.add(SW3_ETH1);
 
         MultiPointToSinglePointIntent intent =
-                new MultiPointToSinglePointIntent(APPID,
-                        selectorBuilder.build(), treatmentBuilder.build(),
-                        ingressPoints, SW4_ETH1);
+                MultiPointToSinglePointIntent.builder()
+                        .appId(APPID)
+                        .selector(selectorBuilder.build())
+                        .treatment(treatmentBuilder.build())
+                        .ingressPoints(ingressPoints)
+                        .egressPoint(SW4_ETH1)
+                        .build();
 
         // Setup the expected intents
         intentService.submit(eqExceptId(intent));
@@ -357,10 +365,13 @@
         ingressPointsNew.add(SW4_ETH1);
 
         MultiPointToSinglePointIntent intentNew =
-                new MultiPointToSinglePointIntent(APPID,
-                                                  selectorBuilderNew.build(),
-                                                  treatmentBuilderNew.build(),
-                                                  ingressPointsNew, SW2_ETH1);
+                MultiPointToSinglePointIntent.builder()
+                        .appId(APPID)
+                        .selector(selectorBuilderNew.build())
+                        .treatment(treatmentBuilderNew.build())
+                        .ingressPoints(ingressPointsNew)
+                        .egressPoint(SW2_ETH1)
+                        .build();
 
         // Set up test expectation
         reset(intentService);
@@ -592,9 +603,13 @@
             }
         }
         MultiPointToSinglePointIntent intent =
-                new MultiPointToSinglePointIntent(APPID,
-                        selectorBuilder.build(), treatmentBuilder.build(),
-                        ingressPoints, egressPoint);
+                MultiPointToSinglePointIntent.builder()
+                        .appId(APPID)
+                        .selector(selectorBuilder.build())
+                        .treatment(treatmentBuilder.build())
+                        .ingressPoints(ingressPoints)
+                        .egressPoint(egressPoint)
+                        .build();
         return intent;
     }