feature request: add support for homescreen icon on mobile phones

[ScrumpyJack]

short of an app client for lets-chat, i just have a shortcut on my homescreen. can you add support for custom icon? for apple iOS, it's here: https://developer.apple.com/library/content/documentation/AppleApplications/Reference/SafariWebContent/ConfiguringWebApplications/ConfiguringWebApplications.html