Change the default port for the development servers

5000 is used by Control Center on macOS, so this will likely annoy
at least a few developers.

This is based on opencast#346, so that should be reviewed and merged first.

app/src/setupProxy.js

@@ -1,6 +1,6 @@
 const { createProxyMiddleware } = require("http-proxy-middleware");
 
-const port = process.env.PROXY_PORT || 5000;
+const port = process.env.PROXY_PORT || 5001;
 
 module.exports = function (app) {
     app.use(

proxyServer.js

@@ -5,7 +5,7 @@ const requestDigest = require('request-digest');
 const urlParser = require('url-parse');
 
 const app = express();
-const port = process.env.PORT || 5000;
+const port = process.env.PORT || 5001;
 
 // Get values of proxy host, username and password from npm command
 let args = process.argv,

staticServer.js

@@ -2,7 +2,7 @@ const path = require("path");
 const express = require("express");
 
 const app = express();
-const port = process.env.PORT || 5000;
+const port = process.env.PORT || 5001;
 
 app.get("/*", express.static(path.join(__dirname, "test/app/GET")));