Fix S3 path-style URL for host with dots for buckets that are placed in other regions than us-east-1

[Bonias]

#2359 added support for bucket names with period, but this only works for us-east-1 region. For other regions s3.{aws-region}.amazonaws.com needs to be used (see https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingBucket.html#access-bucket-intro).

This PR adds support for bucket names with period that are placed in regions other than us-east-1.

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Also, I'm wondering about one other thing regarding virtual-hosted–style URL. https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingBucket.html#access-bucket-intro says:

Buckets created in Regions launched after March 20, 2019 are not reachable via the https://bucket.s3.amazonaws.com naming scheme.

Should carrierwave be updated to use http://{bucket}.s3.{aws-region}.amazonaws.com? If so should it:

• use http://{bucket}.s3.{aws-region}.amazonaws.com for all regions (this is what both aws-sdk-s3, carrierwave-aws do and kind of what fog-aws does; fog-aws uses http://{bucket}.s3-{aws-region}.amazonaws.com),
• use http://{bucket}.s3.{aws-region}.amazonaws.com only for regions created after March 20, 2019? (in that case carrierwave would require to have a list of regions created before March 20, 2019)

?

[mshibuya]

Awesome, thanks!