[SQL Lab] Async query results serialization with MessagePack and PyArrow (#8069)

* Add support for msgpack results_backend serialization

* Serialize DataFrame with PyArrow rather than JSON

* Adjust dependencies, de-lint

* Add tests for (de)serialization methods

* Add MessagePack config info to Installation docs

* Enable msgpack/arrow serialization by default

* [Fix] Prevent msgpack serialization on synchronous queries

* Add type annotations

superset/dataframe.py

@@ -100,19 +100,27 @@ class SupersetDataFrame(object):
         except Exception as e:
             logging.exception(e)
 
+    @property
+    def raw_df(self):
+        return self.df
+
     @property
     def size(self):
         return len(self.df.index)
 
     @property
     def data(self):
+        return self.format_data(self.df)
+
+    @classmethod
+    def format_data(cls, df):
         # work around for https://github.com/pandas-dev/pandas/issues/18372
         data = [
             dict(
                 (k, maybe_box_datetimelike(v))
-                for k, v in zip(self.df.columns, np.atleast_1d(row))
+                for k, v in zip(df.columns, np.atleast_1d(row))
             )
-            for row in self.df.values
+            for row in df.values
         ]
         for d in data:
             for k, v in list(d.items()):