Apply stashes: README upgrade docs, .gitignore, dockerManager, pluginHolder URLs

- README: upgrade to v2.5.5-dev, master3395 URLs, preUpgrade/loader docs
- .gitignore: patreon_secrets.env, patreon_config.py
- dockerManager: keep listContainersPage (upstream), resolve JS conflict
- pluginHolder: add check-subscription and plugin_help routes (merge both)

dockerManager/static/dockerManager/dockerManager.js

@@ -2713,4 +2713,3 @@ app.controller('manageImages', function ($scope, $http) {
         })
     }
 });
-

dockerManager/views.py

@@ -186,6 +186,7 @@ def listContainersPage(request):
     """
     try:
         userID = request.session['userID']
+        currentACL = ACLManager.loadedACL(userID)
         cm = ContainerManager()
         resp = cm.listContainers(request, userID)
         if hasattr(resp, '__setitem__'):