Add data-sharing with security incompatiblity warning (#979)

* Add data-sharing with security incompatiblity warning

Signed-off-by: Juan Lopez Fernandez <juanlopez@eprosima.com>

* Apply suggestion

Signed-off-by: Juan Lopez Fernandez <juanlopez@eprosima.com>

---------

Signed-off-by: Juan Lopez Fernandez <juanlopez@eprosima.com>

Author: juanlofer-eprosima

docs/fastdds/security/includes/intro.rst

@@ -44,4 +44,7 @@ and its value (:class:`std::string`).
   However, it is possible to configure basic system security settings, i.e. authentication, access control and
   encryption, to Fast DDS without this knowledge.
 
+.. warning::
+  The use of security plugins is incompatible with :ref:`Data-sharing delivery <datasharing-delivery>`.
+
 The following sections describe how to configure each of these properties to set up the Fast DDS security plugins.

docs/fastdds/transport/datasharing.rst

@@ -61,6 +61,7 @@ This feature is available only if the following requirements are met:
   i.e., its |TopicDataType::is_bounded-api| member function returns true.
 * The Topic :ref:`is not keyed<dds_layer_topic_keyed_data_types>`.
 * The DataWriter is configured with |PREALLOCATED_MEMORY_MODE-api| or |PREALLOCATED_WITH_REALLOC_MEMORY_MODE-api|.
+* No :ref:`security <security>` plugins are used.
 
 There is also a limitation with the DataReader's HistoryQos.
 Using Data-sharing mechanism, the DataWriter's history is shared with the DataReaders.