Changes to captions on posts

[x] remove CSS hiding caption on featured image
[ ] define new function sfpp_get_featured_hero() that extends the behavior of largo_get_featured_hero() to check if the caption is empty, and if it is, try the post_content instead https://github.com/INN/largo/blob/590181982d22a5444eb3c5ccca58ea8b56db12f7/inc/featured-media.php#L119-L135
[ ] define replacement functions for largo_hero() that uses the replacement sfpp_get_featured_hero(), and replace it in all the partials in this repo that use largo_hero()
[ ] review other uses of largo_hero() in largo and contemplate copying them ing
[x] leave documentation trail of this massive shimming

INN / umbrella-sfpublicpress