HUDI-123 Rename code packages/constants to org.apache.hudi (#830)

- Rename com.uber.hoodie to org.apache.hudi
- Flag to pass com.uber.hoodie Input formats for hoodie-sync
- Works with HUDI demo. 
- Also tested for backwards compatibility with datasets built by com.uber.hoodie packages
- Migration guide : https://cwiki.apache.org/confluence/display/HUDI/Migration+Guide+From+com.uber.hoodie+to+org.apache.hudi

hudi-common/src/test/resources/complex-test-evolved.avsc

@@ -0,0 +1,17 @@
+{
+  "namespace": "example.avro",
+  "type": "record",
+  "name": "User",
+  "fields": [
+    {"name": "field1", "type": ["null", "string"], "default": null},
+    {"name": "field2", "type": ["null", "string"], "default": null},
+    {"name": "name", "type": ["null", "string"], "default": null},
+    {"name": "favoriteIntNumber",  "type": ["null", "int"], "default": null},
+    {"name": "favoriteNumber",  "type": ["null", "long"], "default": null},
+    {"name": "favoriteFloatNumber",  "type": ["null", "float"], "default": null},
+    {"name": "favoriteDoubleNumber",  "type": ["null", "double"], "default": null},
+    {"name": "tags", "type": ["null", {"values": ["null", {"fields": [{"default": null, "type": ["null", "string"], "name": "item1"}, {"default": null, "type": ["null", "string"], "name": "item2"} ], "type": "record", "name": "tagsMapItems"} ], "type": "map"} ], "default": null},
+    {"default": null, "name": "testNestedRecord", "type": ["null", {"fields": [{"default": null, "name": "isAdmin", "type": ["null", "boolean"] }, {"default": null, "name": "userId", "type": ["null", "string"] } ], "name": "notes", "type": "record"}]},
+    {"default": null, "name": "stringArray", "type": ["null", {"items": "string", "type": "array"}]}
+  ]
+}