Support other partitions like aws-cn aws-us-gov

[ron-liu]

Describe the Feature

I am working on cn-north-1, when given the below simple usages, it will complain the error: Error putting S3 policy: MalformedPolicy: Policy has invalid resource.

module "cloudfront-s3-cdn" {
  source = "cloudposse/cloudfront-s3-cdn/aws"
  # version = "0.78.0"

  namespace         = "site"
  stage             = "prod"
  name              = "www-mysite"
  aliases           = ["www.mysite.cn", "mysite.cn"]
  dns_alias_enabled = true
  parent_zone_name  = "mysite.cn"

  price_class       = "PriceClass_All"
  ipv6_enabled      = false
}

I think the following lines cause the issue, it assumes everyone is in aws partition.

• https://github.com/cloudposse/terraform-aws-cloudfront-s3-cdn/blob/master/main.tf#L120,
• https://github.com/cloudposse/terraform-aws-cloudfront-s3-cdn/blob/master/main.tf#L132
• https://github.com/cloudposse/terraform-aws-cloudfront-s3-cdn/blob/master/main.tf#L150

Expected Behavior

It should work even for aws cn.

Describe Ideal Solution

Might should introduce a variable called partition, which default to aws, can be set to aws-cn or aws-us-gov.

Alternatives Considered

Couldn't walk around. May be we should create S3 ourself.

Additional Context

N/A