6067 annotation manager (#6913)

* [android] - AnnotationManager and InfoWindowManager refactor

* make AnnotationManager independent from MapView/MapboxMap, add IconManager,

* make code unit testable

* added some class level documentation (for internal use)

platform/android/MapboxGLAndroidSDKTestApp/src/test/java/com/mapbox/mapboxsdk/maps/MapboxMapTest.java

@@ -79,10 +79,13 @@ public class MapboxMapTest {
     @Mock
     MapboxMap.OnMyBearingTrackingModeChangeListener mMyBearingTrackingModeChangeListener;
 
+    @Mock
+    IconManager iconManager;
+
     @Before
     public void beforeTest() {
         MockitoAnnotations.initMocks(this);
-        mMapboxMap = new MapboxMap(mMapView);
+        mMapboxMap = new MapboxMap(mMapView, iconManager);
     }
 
     @Test