Move to OpenAPI spec as API source of truth

[finestructure]

We've uncovered some issues with generating the OpenAPI spec from VaporToOpenAPI annotations. We're also blocked from bumping this dependency to the next major release due to a compile error.

Finally, Honza makes some great points why starting from the OpenAPI spec as the source of truth is good best practise.

We should take a stab at switching to this approach.

[heckj]

I guess I shouldn't continue to babble away on a closed issue, huh? ;-)

As a related note, the VaporToOpenAPI issue might be resolved with a version update to 4.4.3 per dankinsoid/VaporToOpenAPI#17 (although it might also require an update to an example declaration - uncertain there, but I'll try and look)