Containerised distribution of Guardian main branch

[tonytw1]

What does this change?

Produces container images for a generalised Grid install based on the Guardian's main branch.

Reasonably opinionated towards "we use AWS services but we don't necessarily run the application on AWS".

• Disables AWS CloudWatch and Kineses metrics to simplify the AWS dependencies.
• Switches to ENV variable access tokens for AWS access
• Alters the service URL scheme to present the Grid microservices under a single hostname (which makes local development and deployment behind a single load balancer simpler)
• Removes the InnerServiceStatusCheckController as this is less relevant if deployed with a container orchastator.
• Simplifies Reaper configuration to not need an additional S3 bucket.
• Removes Guardian specific Composer usage stream consumer and Guardian Content API integration. The Usage API remains intact.
• Migrates to imgproxy for image previews. Does not build imgops.

How should a reviewer test this change?

How can success be measured?

Who should look at this?

Tested? Documented?

• locally by committer
• locally by Guardian reviewer
• on the Guardian's TEST environment
• relevant documentation added or amended (if needed)