Improve testbed benchmarks results visualization to easily tell results per version

[mx-psi]

We have benchmarks results available on https://opentelemetry.io/docs/collector/benchmarks/, however there are several issues with this page:

1. The page is not easily discoverable: in the last month it got fewer than 1k views and it is not within the top 200 most visited sections within opentelemetry.io
2. It is not easy to tell the results per version, only per commit
3. The hover tooltip is excessively detailed
4. It is hard to understand the graphs

We should at a minimum:

• Link to this page in the README of components that have a continous benchmark
• Make it easy to tell the benchmark results per version

Other improvements would be nice but, I argue, are of lower priority.