[REF] owl: move metadata into __info__

This differentiate better metadata and owl exported values.  Also, and
this is the goal, it gives a space to add extra keys in the future.

extras/playground/app.js

@@ -153,7 +153,7 @@ owl.utils.whenReady(startApp);`;
 class App extends owl.Component {
   constructor(...args) {
     super(...args);
-    this.version = owl._version;
+    this.version = owl.__info__.version;
     this.SAMPLES = SAMPLES;
     this.widgets = { TabbedEditor };
 
@@ -349,7 +349,7 @@ class TabbedEditor extends owl.Component {
 //------------------------------------------------------------------------------
 // Application initialization
 //------------------------------------------------------------------------------
-document.title = `${document.title} (v${owl._version})`;
+document.title = `${document.title} (v${owl.__info__.version})`;
 document.addEventListener("DOMContentLoaded", async function() {
   const templates = await owl.utils.loadTemplates("templates.xml");
   const qweb = new owl.QWeb(templates);

rollup.config.js

@@ -9,6 +9,6 @@ export default {
     format: "iife",
     name: "owl",
     extend: true,
-    outro: `exports._version = '${version}';\nexports._date = '${new Date().toISOString()}';\nexports._hash = '${git.short()}';\nexports._url = 'https://github.com/odoo/owl';`
+    outro: `exports.__info__.version = '${version}';\nexports.__info__.date = '${new Date().toISOString()}';\nexports.__info__.hash = '${git.short()}';\nexports.__info__.url = 'https://github.com/odoo/owl';`
   }
 };

src/index.ts

@@ -17,5 +17,7 @@ export { QWeb } from "./qweb_core";
 export { connect, Store } from "./store";
 import * as _utils from "./utils";
 
+export const __info__ = {}
+
 
 export const utils = _utils;