[AIRFLOW-3073] Add note-Profiling feature not supported in new webser…

…ver (apache#3909)

Adhoc queries and Charts features are no longer supported in new
FAB-based webserver and UI. But this is not mentioned at all in the doc
"Data Profiling" (https://airflow.incubator.apache.org/profiling.html)

This commit adds a note to remind users for this.

docs/profiling.rst

@@ -1,6 +1,12 @@
+.. TODO: This section would be removed after we migrate to www_rbac completely.
+
 Data Profiling
 ==============
 
+.. note::
+   ``Adhoc Queries`` and ``Charts`` are no longer supported in the new FAB-based webserver
+   and UI, due to security concerns.
+
 Part of being productive with data is having the right weapons to
 profile the data you are working with. Airflow provides a simple query
 interface to write SQL and get results quickly, and a charting application