Fix WebSocket over HTTPS not working

Regression from openhab#1711.
Fixes openhab/openhab-webui#3125.

Signed-off-by: Florian Hotze <dev@florianhotze.com>

Author: florian-h05

distributions/openhab/src/main/resources/runtime/etc/jetty.xml

@@ -160,16 +160,25 @@
 						</Item>
 						<Item>
 							<New class="org.eclipse.jetty.alpn.server.ALPNServerConnectionFactory">
-								<Arg>h2</Arg>
+								<Arg>h2,http/1.1</Arg>
 							</New>
 						</Item>
+						<!-- HTTP/2 over TLS -->
 						<Item>
 							<New class="org.eclipse.jetty.http2.server.HTTP2ServerConnectionFactory">
 								<Arg name="config">
 									<Ref refid="httpConfig" />
 								</Arg>
 							</New>
 						</Item>
+						<!-- WebSockets (HTTP/1.1) -->
+						<Item>
+							<New class="org.eclipse.jetty.server.HttpConnectionFactory">
+								<Arg name="config">
+									<Ref refid="httpConfig" />
+								</Arg>
+							</New>
+						</Item>
 					</Array>
 				</Arg>
 				<Set name="name">