Radial - Picture Positioning

[Mason62]

Picture positions change and need adjustment any time radial view is used. For instance, there's sometimes three radials at the top and you can adjust pictures for those three. Next time, there might be only 2 radials at the top and therefore pictures and radials are out of sync and messy. Since this is supposed to be a dynamic report, it needs to cater for possible changes based on filters etc.

[mattbrehmer]

Related to #102 (Images do not follow resizing/going to Focus mode) and #84 (Some data points around images cannot be selected in radial representation), and not specific to the Power BI version of Timeline Storyteller.