Retention values that are "too big" overflow and cause confusing error messages

[danxmoran]

Steps to reproduce:

1. Attempt to create a bucket with retention.EverySeconds = 999999

Expected behavior:
Either the request succeeds, or a helpful error explaining the problem is returned

Actual behavior:

internal error: retention policy duration must be at least 1h0m0s

Debugging showed me that the retention value is overflowing in this logic.

The same bug is also present on bucket-update requests. See the original community report here.