+htp #20535 add checkSameOrigin directive to HeaderDirectives (#20560)

*  #20535 add checkSameOrigin directive to WebSocketDirectives

* refactoring + add docs

* refactoring + cleanup in docs

* fix types and conversions in the InvalidOriginHeaderRejection

* simplify InvalidOriginHeaderRejection to InvalidOriginRejection

akka-docs/rst/java/http/routing-dsl/directives/header-directives/checkSameOrigin.rst

@@ -0,0 +1,17 @@
+.. _-checkSameOrigin-java-:
+
+checkSameOrigin
+===============
+
+Description
+-----------
+Checks that request comes from the same origin. Extracts the ``Origin`` header value and verifies that allowed range
+contains the obtained value. In the case of absent of the ``Origin`` header rejects with a ``MissingHeaderRejection``.
+If the origin value is not in the allowed range rejects with an ``InvalidOriginHeaderRejection``
+and ``StatusCodes.FORBIDDEN`` status.
+
+Example
+-------
+Checking the ``Origin`` header:
+
+.. includecode:: ../../../../code/docs/http/javadsl/server/directives/HeaderDirectivesExamplesTest.java#checkSameOrigin

akka-docs/rst/java/http/routing-dsl/directives/header-directives/index.rst

@@ -17,3 +17,4 @@ response headers use one of the :ref:`RespondWithDirectives-java`.
    optionalHeaderValueByName
    optionalHeaderValueByType
    optionalHeaderValuePF
+   checkSameOrigin