(core) i18

Summary:
Adding initial work for localization support.

Summary in https://grist.quip.com/OtZKA6RHdQ6T/Internationalization-and-Localization

Test Plan: Not yet

Reviewers: paulfitz

Reviewed By: paulfitz

Subscribers: paulfitz

Differential Revision: https://phab.getgrist.com/D3633

app/client/ui/setupPage.ts

@@ -1,4 +1,5 @@
 import {get as getBrowserGlobals} from 'app/client/lib/browserGlobals';
+import {setupLocale} from 'app/client/lib/localization';
 import {AppModel, TopAppModelImpl} from 'app/client/models/AppModel';
 import {setUpErrorHandling} from 'app/client/models/errors';
 import {buildSnackbarDom} from 'app/client/ui/NotifyUI';
@@ -19,6 +20,8 @@ export function setupPage(buildPage: (appModel: AppModel) => DomContents) {
   attachCssRootVars(topAppModel.productFlavor);
   addViewportTag();
 
+  void setupLocale();
+
   // Add globals needed by test utils.
   G.window.gristApp = {
     testNumPendingApiRequests: () => BaseAPI.numPendingRequests(),