Use a field for FeaturedText instead of a body slice

[gestchild]

Remove the featured label from the text slice and have a separate field for the featured text on custom types that require it. The featured text doesn't feel like it should be a slice as there should only be one on a page and the logic around how and when it displays is not obvious to content editors. For example, if a text slice has a featured label but is not the first slice, then it is not rendered at all.