Roll out KUBERNETES_HONOR_ENTRYPOINT

In !3095 (merged) & !3212 (merged), we made the change so that if the kubernetes attachment strategy is used and FF_KUBERNETES_HONOR_ENTRYPOINT is turned on, then the docker image's entrypoint will be honored.

We need a strategy to roll this out to get feedback and validate the feature.

The main question is, who should we roll this out to? Should we contact some customer's who we know need this feature?

To rollout

• get feedback
• enable FF_KUBERNETES_HONOR_ENTRYPOINT by default
• update https://docs.gitlab.com/runner/configuration/tls-self-signed.html#kubernetes
• get more feedback
• remove FF_KUBERNETES_HONOR_ENTRYPOINT
• update https://docs.gitlab.com/runner/configuration/tls-self-signed.html#kubernetes