Deterministic ordering of maps in the OpenAPI response.

[eak24]

I've found that the ordering of the schemas and the paths can appear to be pretty random. It would be nice if these would be always alphabetically ordered... I will try switching all LinkedHashMaps and the like to be TreeMaps and see how it goes in a PR. Unless there is some profound meaning to return everything in the insertionOder? I can't imagine there is, since the read method takes in what could be an unordered set.

[eak24]

@frantuma here's another PR that should help me fix all the other tests in #3469 by clarifying the failures if there are any - because #3469 seems to switch insertion order by being more efficient in not re-processing types multiple times.

[frantuma]

A solution has been implemented in #3740, see PR comment for details and usage scenarios. Closing this ticket, any further issues in this area should be reported in a new or not closed ticket.