HPCC-20000 DOCS: Output Portal HTML to docs directory

Signed-off-by: G-Pan <greg.panagiotatos@lexisnexis.com>

docs/BuildTools/cmake_config/PortalHTML.txt

@@ -24,7 +24,7 @@ IF(MAKE_DOCS)
   SET(PORTAL_HTML_ZIP "portal_html_${DOC_LANG}_zip")
   ADD_CUSTOM_TARGET(${PORTAL_HTML_ZIP} ALL
            COMMAND zip -r "portal_html_${DOC_LANG}.zip" ${PORTAL_HTML_DIR}
-           WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/${CMAKE_BUILD_TYPE}/
+           WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/${CMAKE_BUILD_TYPE}/docs/
            DEPENDS ${HELP_DEPENDENCIES}
            )
   set_property(GLOBAL APPEND PROPERTY DOC_TARGETS ${PORTAL_HTML_ZIP})