Add application icons

It would be really cool if gitlab specified an application icon which can be used for example when a user pins it to their smartphone's home screen or for the speed dial pages of some desktop browsers.

To do this, the following (or similar) should be added to the layout's head tag:

    <!-- For iOS home screen -->
    <link rel="apple-touch-icon" sizes="57x57" href="/apple-touch-icon-114.png">
    <link rel="apple-touch-icon" sizes="114x114" href="/apple-touch-icon-114.png">
    <link rel="apple-touch-icon" sizes="72x72" href="/apple-touch-icon-144.png">
    <link rel="apple-touch-icon" sizes="144x144" href="/apple-touch-icon-144.png">

    <!-- For windows 8 pinned websites. This should probably be a little larger -->
    <meta name="msapplication-TileImage" content="/tileimage.png">
    <meta name="msapplication-TileColor" content="#ffffff">

I think there's another format for android but I'm not quite sure. Opera lets its users select from both formats for their speed dial page.

I opened the same issue for Gitlab CI as gitlab-org/gitlab-ci#200

The latest blog post makes this even more relevant.

Reassigned to @rspeicher

mentioned in merge request !944 (merged)

Status changed to closed by commit 98291295

It's unfortunate that Android was overlooked in this.

Icons are just a part of this. Chrome for Android's "Add to Homescreen" makes use of a Manifest for Web Application specification.

@jonathon-reinhart I had trouble finding information for Android's implementation (thank you for those links!) and don't have a device I could test with myself. If you could submit a MR with Android support I'm sure that would be appreciated.

mentioned in merge request !14785