Replace sprockets/browserify with Webpack (#2617)

* Replace browserify with webpack

* Add react-intl-translations-manager

* Do not minify in development, add offline-plugin for ServiceWorker background cache updates

* Adjust tests and dependencies

* Fix production deployments

* Fix tests

* More optimizations

* Improve travis cache for npm stuff

* Re-run travis

* Add back support for custom.scss as before

* Remove offline-plugin and babili

* Fix issue with Immutable.List().unshift(...values) not working as expected

* Make travis load schema instead of running all migrations in sequence

* Fix missing React import in WarningContainer. Optimize rendering performance by using ImmutablePureComponent instead of
React.PureComponent. ImmutablePureComponent uses Immutable.is() to compare props. Replace dynamic callback bindings in
<UI />

* Add react definitions to places that use JSX

* Add Procfile.dev for running rails, webpack and streaming API at the same time

app/javascript/mastodon/locales/index.js

@@ -0,0 +1,57 @@
+import ar from './ar.json';
+import en from './en.json';
+import de from './de.json';
+import es from './es.json';
+import fa from './fa.json';
+import he from './he.json';
+import hr from './hr.json';
+import hu from './hu.json';
+import io from './io.json';
+import it from './it.json';
+import fr from './fr.json';
+import nl from './nl.json';
+import no from './no.json';
+import oc from './oc.json';
+import pt from './pt.json';
+import pt_br from './pt-BR.json';
+import uk from './uk.json';
+import fi from './fi.json';
+import eo from './eo.json';
+import ru from './ru.json';
+import ja from './ja.json';
+import zh_hk from './zh-HK.json';
+import zh_cn from './zh-CN.json';
+import bg from './bg.json';
+import id from './id.json';
+
+const locales = {
+  ar,
+  en,
+  de,
+  es,
+  fa,
+  he,
+  hr,
+  hu,
+  io,
+  it,
+  fr,
+  nl,
+  no,
+  oc,
+  pt,
+  'pt-BR': pt_br,
+  uk,
+  fi,
+  eo,
+  ru,
+  ja,
+  'zh-HK': zh_hk,
+  'zh-CN': zh_cn,
+  bg,
+  id,
+};
+
+export default function getMessagesForLocale(locale) {
+  return locales[locale];
+};