s3api should return more-useful error message when quotas are exceeded

[Tim Burke]

Currently, we translate the 413 coming out of account/container quota middlewares to a 400 with a body like

   <Error>
     <Code>EntityTooLarge</Code>
     <Message>Your proposed upload exceeds the maximum allowed object size.</Message>
     <RequestId>...</RequestId>
   </Error>

AWS doesn't really have the same notion of account/bucket quotas (they're happy to just keep charging you money) so I get why this was the closest approximation we could find... but I've often had users and support get confused and waste time checking whether the client tried to upload more than 5GB at a time, or copy an object that was >5GB. It'd be much more useful to have the message include something about quotas -- error code should maybe stay the same, though.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/749382
Committed: https://git.openstack.org/cgit/openstack/swift/commit/?id=f8a9a6e11620d1abc537bcef107fa21af53fc6d2
Submitter: Zuul
Branch: master

commit f8a9a6e11620d1abc537bcef107fa21af53fc6d2
Author: Tim Burke <email address hidden>
Date: Tue Sep 1 12:43:03 2020 -0700

    s3api: Make quota-exceeded errors more obvious

    Change-Id: Ia8db40227343e9c4555267c62072a1c9bfc28c66
    Closes-Bug: #1893811