[IMP] app: add global values at compile time

This commit, add a new configuration on the App: globalValues.
It's a global object of elements available at compilations.

For instance:
```js
    const app = new App(SomeComponent, {
      globalValues: {
        plop: (string: any) => {
          steps.push(string);
        },
      },
    });
```

The plop function will be available at the compilation, so it can be
used on the templates :
```xml
<div t-on-click="() => __globals__.plop('click')" class="my-div"/>
```

src/index.ts

@@ -13,5 +13,6 @@ TemplateSet.prototype._compileTemplate = function _compileTemplate(
     translateFn: this.translateFn,
     translatableAttributes: this.translatableAttributes,
     customDirectives: this.customDirectives,
+    hasGlobalValues: this.hasGlobalValues,
   });
 };