Expose whether cluster mode is enabled over /api/instance/config

docs/REST.md

@@ -32,6 +32,7 @@ Configuration of the instance relating to media
 ```
 {
 	rtmp: {
+		cluster: false,
 		port: 1935,
 		ping_timeout: 60
 	},

src/http.ts

@@ -168,6 +168,7 @@ async function initAPI() {
 	app.get('/api/instance/config', (req, res) => {
 		res.json({
 			rtmp: {
+				cluster: config['rtmp']['cluster'],
 				port: config['rtmp']['port'],
 				ping_timeout: config['rtmp']['ping_timeout']
 			},