Minimize manual steps in operator release process

The [current release process](https://cockroachlabs.atlassian.net/wiki/spaces/KO/pages/1753841712/Cockroach+Operator+Release+Process) requires quite a lot manual steps before we can run automation. This includes version bump, manifest generation, updating some files.

It's very easy to miss a step or have do something wrong, especially given the fact that some steps run bazel targets.

It would be great to eliminate most of the manual preparation steps, so we can run all those in TeamCity.

See also https://github.com/cockroachdb/cockroach-operator/pull/550