S3 Proxy GetBucketAcl incorrect result

[jonaustin09]

Describe the bug
When running GetBucketAcl_success integration test, it returns incorrect result.

Result
expected grants to be [{0x1400031e040 FULL_CONTROL {}} {0x1400031e080 READ_ACP {}} {0x1400031e0c0 WRITE {}}], instead got [{0x14000393dc0 FULL_CONTROL {}} {0x140004100c0 READ_ACP {}} {0x140004103c0 WRITE {}}]

To Reproduce

./versitygw test -a a -s s --endpoint http://localhost:7071 GetBucketAcl_success

Expected behavior
It has to successfully pass the integration test

[benmcclelland]

for this one, I think we need a way to store our own ACLs separately from the backend ACLs. So we dont want to forward the ACL to the backend, we need to encode it in the bucket metadata or something else.