Add support for server-side events and tests

User can POST to web endpoint in SSE style, i.e:

HTTP/1.1
Content-Type: text/event-stream

data:foo

data:bar

Will be converted to a Flux with values foo and bar

spring-cloud-function-deployer/src/test/java/org/springframework/cloud/function/deployer/FunctionExtractingFunctionCatalogIntegrationTests.java

@@ -38,7 +38,8 @@ public class FunctionExtractingFunctionCatalogIntegrationTests {
 	public static void open() {
 		port = SocketUtils.findAvailableTcpPort();
 		// System.setProperty("debug", "true");
-		context = new ApplicationRunner().start("--server.port=" + port);
+		context = new ApplicationRunner().start("--server.port=" + port,
+				"--spring.cloud.stream.enabled=false");
 	}
 
 	@AfterClass