Fix test failures and further reroll, among which: CommentlinkBuilder::buildCommentedEntityLinks() changes taken over into CommentDefaultFormatter::buildLinks() (from review #2318251-21)
small change: imho building the new-comment data on post-render-cache is not useful for non-node entities. (Also: the code works, but the definition of “new” is always 30 days, which is less than useful.)
I think there was a mistake in teaser vs default links.
old field config schema also needs to be deleted
Move ‘default_mode’ from display setting into comment type, and rename ‘threading_mode’.
Unfinished (because not working with comment form on separate page, but working on inline form already): store redirect-url-view-mode in comment form.