merge certificates.js and nginx.js to reverseproxy.js

when certs change, we have to call into nginx anyway. since they
go hand in hand, just merge those files. modern reverse proxies
do this job integrated already.

src/cloudron.js

@@ -28,12 +28,12 @@ var assert = require('assert'),
     eventlog = require('./eventlog.js'),
     locker = require('./locker.js'),
     mailer = require('./mailer.js'),
-    nginx = require('./nginx.js'),
     os = require('os'),
     path = require('path'),
     paths = require('./paths.js'),
     platform = require('./platform.js'),
     progress = require('./progress.js'),
+    reverseProxy = require('./reverseproxy.js'),
     safe = require('safetydance'),
     settings = require('./settings.js'),
     shell = require('./shell.js'),
@@ -81,7 +81,7 @@ function initialize(callback) {
 
     async.series([
         settings.initialize,
-        nginx.configureDefaultServer,
+        reverseProxy.configureDefaultServer,
         cron.initialize, // required for caas heartbeat before activation
         onActivated
     ], callback);