Infowindow - layers list

[asemoller]

Fixes #1521.

I know it's unclear whether it should be optional to have a list layout for the infowindow, but since that's how we've developed this layout, I'll submit it anyway.

Configured like this:

"infowindowOptions": {
          "listLayout": true
        }

Also fixes #1434.

[johnnyblasta]

Tested and it works as supposed to.
Holding back an approvable since it's unclear about the config option.