Release resource estimator 2.0

Created by: abeatrix

Follow up on https://github.com/sourcegraph/resource-estimator/pull/13

This PR updates the resource estimator version number to the build number from https://github.com/sourcegraph/resource-estimator/pull/13

The additional information section has been removed from the actual resource estimator and added to the resource_estimator.md file instead so that if we would like to update the additional information section, we won't need to create another build. It also makes link-sharing easier using url fragment

I have also moved the Service overview section to this md file due to the aforementioned reason.

Test plan

Docs update. Tested manually please see screenshots below: