remove docker images from build pipeline

Created by: nicksnyder

All docker images should be produced from our enterprise repository

1. So we can release by pushing a git tag
2. It is simpler to manage docker images from one repository

If there are technical reasons why certain images must be built here currently, I would like to understand those technical reasons and try to come up with a solution that will allow us to build/release from the enterprise repo.

helps https://github.com/sourcegraph/enterprise/issues/13595