(into bug974736) Bug 975210 - Augment Site._render logic to allow for Sponsored Tiles images & text
Set backround image and color to provider supplied
Set background position and size for sponsored tile thumbnail
Only trigger thumbnail capture if we dont have a provider image.
Restore original code styling and move logic into refreshThumbnail.
Use link instead of providerData.
Update the thumbnail background color when refreshing the thumbnail.
Move uri definition next to usage.
Use the type=sponsored instead of sponsored attribute.
Replace imageURI with imageURISpec