openolat#223: added priv. disclaimer to guest join page

src/main/java/org/olat/modules/bigbluebutton/ui/_content/guest_join.html

@@ -31,6 +31,7 @@
 			</div>
 			#end
 		</div>
+		<div class="o_block_large o_warning">$r.translate("meeting.disclaimer.privacy")</div>
 		<div class=o_button_group>
 			$r.render("meeting.join.button")
 		</div>