@ohif/i18n: Fix issues with exports and update docs (#598)

* update i18n version -- already published

* update ohif/i18n version and add modules

* update ohif/i18n version

* update translating documentation

* replace addLocales method and exported modules

* lock files

* Update index.js

* fix(@ohif/i18n): export custom methods in the main i18n object

`initI18n`, `addLocales` and `T` are now being exported inside the main `i18n` object.

* remove unecessary dependencies

* update vtk-extension lock file

docs/latest/essentials/translating.md

@@ -115,9 +115,9 @@ When needed, you can also use available translations _without React_.
 E.g.
 
 ```js
-import { t } from '@ohif/i18n';
-console.log(t('my translated text'));
-console.log(t('$t(Common:Play) my translated text'));
+import { T } from '@ohif/i18n';
+console.log(T('my translated text'));
+console.log(T('$t(Common:Play) my translated text'));
 ```
 
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