Add note in interactive tools docs page informing about `interactivet…

…ools_map_sqlalchemy` setting

Refer to SQLite docs page describing situations where a client/server RDBMS works better and provide an example. Link to the `interactivetools_map_sqlalchemy` on the Galaxy configuration page.

doc/source/admin/special_topics/interactivetools.rst

@@ -102,6 +102,19 @@ The ``gx-it-proxy`` config relates to an important service in the InteractiveToo
 proxy. ``gx-it-proxy`` runs as a separate process listening at port 4002 (by default). HTTP requests are decoded based on
 the URL and headers, then somewhat massaged, and finally forwarded to the correct entry point port of the target InteractiveTool.
 
+.. note::
+
+    Entry point mappings used by the proxy are stored on a SQLite database file located at ``interactivetools_map``. In
+    `some situations <https://www.sqlite.org/whentouse.html#situations_where_a_client_server_rdbms_may_work_better>`_,
+    SQLite may not be the best choice. A common case is a high-availability production setup, meaning that multiple
+    copies of Galaxy are running on different servers behind a load balancer.
+
+    For these situations, there exists an optional |configuration option interactivetools_map_sqlalchemy|_ that allows
+    using any database supported by SQLAlchemy (it overrides ``interactivetools_map``).
+
+.. |configuration option interactivetools_map_sqlalchemy| replace:: configuration option ``interactivetools_map_sqlalchemy``
+.. _configuration option interactivetools_map_sqlalchemy: ../config.html#interactivetools-map-sqlalchemy
+
 .. note::
 
     A previous config option ``interactivetools_shorten_url`` was removed in commit `#73100de <https://github.com/galaxyproject/galaxy/pull/16795/commits/73100de17149ca3486c83b8c6ded74987c68a836>`_