Pipeline updates

[markdboyd]

Changes proposed in this pull request:

• Update pipeline to be self-flying
• Remove triggers based on Terraform state YAML. We don't necessarily need or want this broker to redeploy when Terraform for a given environment (e.g. development) is redeployed. There is no use of Terraform outputs in the pipeline or configuration of the broker
• Remove triggers based on defunct S3 bucket tracking the semver of deployed components
• Update pipeline to use latest hardened containers and general-task iamge

security considerations

The main security facing change here is updating the pipeline to use the latest hardened containers including general-task

[cweibel]

Assuming all the secrets were moved to credhub to allow the self fly, this looks good to me