Publishing an 'ok paper' to arxiv
Have you considered submission to a journal? As reviewers are not identified, it is reasonable to trust their judgement that the paper is "okay", and of course "okay" at a top conference in CS could still be quite good, especially as it's within the top 15%. Although perhaps the top-tier journals would render a similar judgement, there may be a venue where it is appropriate (I'm not familiar with the computer vision area), and you could publish without an excess of additional work.

Alongside this you can (usually) always put a preprint on ArXiv, few journals or conferences take issue with this now, which allows you to make it available in the meantime, regardless of what else you decide to do with it in the future.

However I would definitely not include the reviews. Although there is no rule against doing so, particularly as the reviewers shouldn't be identifiable, it contributes nothing to your research - the reader should be assessing the value themselves. The inclusion of reviews would only indicate that you want to boast about your work, or that you want people to accept it because someone else said it was good.