boto3_s3tests: add tests for lifecycle expiration header

boto3_s3tests: add tests for lifecycle expiration header

The response to a successful PUT or HEAD (or GET) of/on
an object matching any enabled lifecycle expiration rule should
include an x-amz-expiration header for the object.  The
x-amz-expiration header consists of an expiry-date, rule-id tuple
indicating the earliest matching rule and the corresponding
expiration date for the object.

Also, while at it, add test for lifecycle expiration rule with
'Days' : 0, which should both apply and...work.

Signed-off-by: Matt Benjamin <mbenjamin@redhat.com>