Enhance Integration with Spark (#1097)

* add doc for spark

* labelCol equals to label by default

* change title and reformat

* reference about default index type

* fix doc build

* Update website/docs/Examples/Integrate - Spark.md

* update doc

* Added more references

* remove exception case when `y_train.name` is None

* fix broken link

---------

Co-authored-by: Wendong Li <v-wendongli@microsoft.com>
Co-authored-by: Li Jiang <bnujli@gmail.com>

test/spark/test_0sparkml.py

@@ -165,7 +165,6 @@ def test_spark_input_df():
     automl.fit(
         dataframe=df,
         label="Bankrupt?",
-        labelCol="Bankrupt?",
         isUnbalance=True,
         **settings,
     )
@@ -196,7 +195,6 @@ def test_spark_input_df():
         automl.fit(
             dataframe=df,
             label="Bankrupt?",
-            labelCol="Bankrupt?",
             isUnbalance=True,
             **settings,
         )