Add translations

[felixb-wix]

Resolves #5 (see for details)

Limitations:

• Injection of t() into props by connectWithShell will be handled in refactor for connect with shell - fluent connect #6 (fluent connectWithShell API)

[salickc]

@felixb-wix I was under the impression that translations should work out of the box using the i18n provider that all Wix projects are using today. We shouldn't write our own localization solution

import * as i18next from 'i18next';
import * as i18nextXHRBackend from 'i18next-xhr-backend';

// initializing i18n
export default function i18n({locale, baseUrl = ''}) {
  return i18next
    .use(i18nextXHRBackend)
    .init({
      lng: locale,
      fallbackLng: 'en',
      keySeparator: '$',
      interpolation: {
        escapeValue: false
      },
      react: {
        wait: true
      },
      backend: {
        loadPath: `${baseUrl}assets/locale/messages_{{lng}}.json`,
        crossDomain: true
      }
    });
}

// rendering i18n provider
import {I18nextProvider} from 'react-i18next';
ReactDOM.render(
<I18nextProvider i18n={i18n({locale, baseUrl: staticsBaseUrl})}>
    <...>
</I18nextProvider/>)

// get i18n t
import {t} from 'i18next';
t(...)

[felixb-wix]

@salick I did what we discussed in #5. The comment above is a completely different solution. Let's talk about it.

[felixb-wix]

The I18n implementation isn't right, and interceptors implementation was moved to a separate PR #13