Re-work bucket naming rules.

[blkmajik]

Add bucket_name_quirks config option (boolean). This allows you to use a colon in the bucket name for Ceph compatibility with tenants.

Since it's after March 1, 2018 apply the bucket naming rules for bucket creation across the board. Still allow dns_strict to be used if we ever check bucket names for not creation events. See

https://docs.aws.amazon.com/AmazonS3/latest/userguide/bucketnamingrules.html

for details.

[fviard]

Thank you very much for your PR. This would be a worthwhile change.

I did a few reviews to improve this change, and afterward I will be happy to merge it.