Show user avatar and link to user profile

[ryanw-mobile]

in API response, we have
"username": "",

username can be empty, but in case it doesn't, we have an additional block like this:

      "user": {
        "avatar_url": "...",
        "banner_image": "...",
        "banner_url": "...",
        "profile_url": "https://giphy.com/.../",
        "username": "...",
        "display_name": "...",
        "description": "",
        "instagram_url": "...",
        "website_url": "...",
        "is_verified": true
      },

So that:

1. We have a display_name to show, rather than the raw username
2. We have an avatar_url

There are many more possibilities, including showing the user details in a bottom sheet,
but for this stage, if an image comes with a username and the user{} object, we can replace the current "GIF" image type avatar with the actual user images.