Update pipeline to build CSW images

cyber-chalice and csw-concourse-worker still need to be built by this pipeline.

[x] Make sure that the PR updating the cyber-chalice Dockerfile is merged: https://github.com/alphagov/csw-concourse/pull/17
- This will fix the core issue of the pipeline triggering problem identified in https://github.com/alphagov/cyber-security-concourse-base-image/issues/23#issuecomment-707571283, which was that different images would have different versions of Terraform.
- Need to check that the new image allows the csw pipeline in Concourse to pass without issue. Maybe do a manual build + push? (I've only done a manual build, but haven't pushed).
[x] They need to be configured as per the README in their repository: https://github.com/alphagov/csw-concourse
- This includes uploading both semver and latest tags for each image.

alphagov / cyber-security-concourse-base-image