Clean up old pages from S3

[ybyzek]

https://kafka-tutorials.confluent.io/kafka-connect-datagen-ccloud/kafka.html was removed a few months back by PR #856 but it is still a live page.

Why is this happening? I suspect this is because this page persists in S3 and so it keeps getting indexed and discoverable.

This GH issue is two parts:

1. Clean out the S3 bucket and ensure only intended pages are discoverable
2. Handle redirects for bad links, otherwise the current UX is below

[ybyzek]

Solutions to investigate (thanks @colinhicks !)

1. This needs to be changed to use sync https://github.com/confluentinc/kafka-tutorials/blob/master/.semaphore/live-site-deploy.yml#L24 (https://docs.aws.amazon.com/cli/latest/reference/s3/sync.html)
2. https://docs.aws.amazon.com/AmazonS3/latest/userguide/CustomErrorDocSupport.html