Fixes null check for changes to RuntimeCacheProvider
starts fixing up upload prop editor to be the same as the 6.x < one so that it is 100% compatible
Merge remote-tracking branch 'origin/6.1.3' into 7.0.0
Fixed up the media uploader property editor so that it doesn't store any json, this leaves it as fully backwards compatible with 6.x < but also still allows us to upload multiple images if we want.