Add custom PWA install button on interface

[kefranabg]

As PWA add to home screen workflow is different on each platform/browsers, we could add a button on the interface to trigger the installation. It will standardize add to home screen workflow for all browsers.

See official doc
for more informations

[tbetous]

Now, this is not very interesting cause of limited compatibility. We will see in the future when this feature will be more common.

More information about it :

• https://developer.mozilla.org/en-US/docs/Web/API/BeforeInstallPromptEvent
• https://whatwebcando.today/installation.html