Similarly to what has been done for Azure (#48636) and GCS (#48762),
this committ removes the existing Ant fixture that emulates a S3 storage
service in favor of multiple docker-compose based fixtures.
The goals here are multiple: be able to reuse a s3-fixture outside of the
repository-s3 plugin; allow parallel execution of integration tests; removes
the existing AmazonS3Fixture that has evolved in a weird beast in
dedicated, more maintainable fixtures.
The server side logic that emulates S3 mostly comes from the latest
HttpHandler made for S3 blob store repository tests, with additional
features extracted from the (now removed) AmazonS3Fixture:
authentication checks, session token checks and improved response
errors. Chunked upload request support for S3 object has been added
too.
The server side logic of all tests now reside in a single S3HttpHandler class.
Whereas AmazonS3Fixture contained logic for basic tests, session token
tests, EC2 tests or ECS tests, the S3 fixtures are now dedicated to each
kind of test. Fixtures are inheriting from each other, making things easier
to maintain.