Remove StatsController, StatsContainer, and routes

Remove everything related to `StatsController`, `StatsContainer, the
stats route, and the show file.

We are essentially undoing parts of this commit:
ef1dd8c

The functionality of DispatchStats, CertificationStats, and the
StatsContainer have all be deprecated but were not fully removed.
This commit (and PR) removes the deprecated items.

client/app/index.js

@@ -40,7 +40,6 @@ import Error403 from 'app/errors/Error403';
 import Unauthorized from 'app/containers/Unauthorized';
 import OutOfService from 'app/containers/OutOfService';
 import Feedback from 'app/containers/Feedback';
-import StatsContainer from 'app/containers/stats/StatsContainer';
 import Login from 'app/login';
 import TestUsers from 'app/test/TestUsers';
 import TestData from 'app/test/TestData';
@@ -77,7 +76,6 @@ const COMPONENTS = {
   OutOfService,
   Unauthorized,
   Feedback,
-  StatsContainer,
   Hearings,
   PerformanceDegradationBanner,
   Help,
@@ -131,7 +129,6 @@ const componentWrapper = (component) => (props, railsContext, domNodeId) => {
         './login/index',
         './test/TestUsers',
         './test/TestData',
-        './containers/stats/StatsContainer',
         './certification/Certification',
         './manageEstablishClaim/ManageEstablishClaim',
         './hearings/index',

config/routes.rb

@@ -359,8 +359,6 @@
 
   get 'whats-new' => 'whats_new#show'
 
-  get 'stats', to: 'stats#show'
-
   match '/intake/:any' => 'intakes#index', via: [:get]
 
   get "styleguide", to: "styleguide#show"